I tried your proposed solution and it fails in step #3.
After adding the Stratix files into the Arria project I ran the IP upgrade tool and it fails.
Error: 2023.10.31.20:54:09 Error: The system and spd files are targeted to multiple device families "arria10,stratix10". Please regenerate your designs using same device family. If your designs are family-independent, use --device-family to specify one device family.
Error(20327): 2023.10.31.20:48:50 Error: reset_release_stratix: Component s10_user_rst_clkgate_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:48:50 Error: Generation failed with exit code 3: 1 Error, 0 Warnings
Error(20327): 2023.10.31.20:48:50 Error: Device part 1SG280HU2F50E2VG is not a valid part in the device family Arria 10
Error(20327): 2023.10.31.20:48:50 Error: reset_release_stratix: Component s10_user_rst_clkgate_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:48:50 Error: Generation failed with exit code 3: 1 Error, 0 Warnings
Error(20327): 2023.10.31.20:49:07 Error: pll_atx_stratix.xcvr_atx_pll_s10_htile_0: The current selected device "10AX115S2F45I1SG" is invalid, please select a valid device to generate the IP.
Error(20327): 2023.10.31.20:49:07 Error: pll_atx_stratix: Component xcvr_atx_pll_s10_htile_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:49:07 Error: Generation failed with exit code 3: 2 Errors, 0 Warnings
Error(20327): 2023.10.31.20:49:07 Error: Device part 1SG280HU2F50E2VG is not a valid part in the device family Arria 10
Error(20327): 2023.10.31.20:49:07 Error: pll_atx_stratix.xcvr_atx_pll_s10_htile_0: The current selected device "10AX115S2F45I1SG" is invalid, please select a valid device to generate the IP.
Error(20327): 2023.10.31.20:49:07 Error: pll_atx_stratix: Component xcvr_atx_pll_s10_htile_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:49:07 Error: Generation failed with exit code 3: 2 Errors, 0 Warnings
Error(20327): 2023.10.31.20:49:15 Error: fpll_user_stratix.xcvr_fpll_s10_htile_0: The current selected device "10AX115S2F45I1SG" is invalid, please select a valid device to generate the IP.
Error(20327): 2023.10.31.20:49:15 Error: fpll_user_stratix: Component xcvr_fpll_s10_htile_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:49:15 Error: Generation failed with exit code 3: 2 Errors, 1 Warning
Error(20327): 2023.10.31.20:49:15 Error: Device part 1SG280HU2F50E2VG is not a valid part in the device family Arria 10
Error(20327): 2023.10.31.20:49:15 Error: fpll_user_stratix.xcvr_fpll_s10_htile_0: The current selected device "10AX115S2F45I1SG" is invalid, please select a valid device to generate the IP.
Error(20327): 2023.10.31.20:49:15 Error: fpll_user_stratix: Component xcvr_fpll_s10_htile_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:49:15 Error: Generation failed with exit code 3: 2 Errors, 1 Warning
Error(20327): 2023.10.31.20:49:47 Error: serial_lite_iii_stratix.sl3_0: Please select a device that supports a minimum of one of the tiles, L-Tile or H-Tile.
Error(20327): 2023.10.31.20:49:47 Error: serial_lite_iii_stratix.sl3_0: add_connection: There is no interface inst_interlaken_phy.reconfig_clk
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy.inst_phy_adapter.txcore_clock: inst_phy_adapter.txcore_clock must be connected to a clock output
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy.inst_phy_adapter.rxcore_clock: inst_phy_adapter.rxcore_clock must be connected to a clock output
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy: Interface tx_serial_data tried to export unknown interface inst_interlaken_phy.tx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy: Interface rx_serial_data tried to export unknown interface inst_interlaken_phy.rx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0: Interface tx_serial_data tried to export unknown interface inst_sl3_phy.tx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0: Interface rx_serial_data tried to export unknown interface inst_sl3_phy.rx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix: Component sl3_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:49:48 Error: Generation failed with exit code 3: 9 Errors, 35 Warnings
Error(20327): 2023.10.31.20:49:48 Error: Device part 1SG280HU2F50E2VG is not a valid part in the device family Arria 10
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0: Please select a device that supports a minimum of one of the tiles, L-Tile or H-Tile.
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0: add_connection: There is no interface inst_interlaken_phy.reconfig_clk
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy.inst_phy_adapter.txcore_clock: inst_phy_adapter.txcore_clock must be connected to a clock output
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy.inst_phy_adapter.rxcore_clock: inst_phy_adapter.rxcore_clock must be connected to a clock output
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy: Interface tx_serial_data tried to export unknown interface inst_interlaken_phy.tx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0.inst_sl3_phy: Interface rx_serial_data tried to export unknown interface inst_interlaken_phy.rx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0: Interface tx_serial_data tried to export unknown interface inst_sl3_phy.tx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix.sl3_0: Interface rx_serial_data tried to export unknown interface inst_sl3_phy.rx_serial_data
Error(20327): 2023.10.31.20:49:48 Error: serial_lite_iii_stratix: Component sl3_0 does not support selected device family Arria 10
Error(20327): 2023.10.31.20:49:48 Error: Generation failed with exit code 3: 9 Errors, 35 Warnings
Error(14923): Error upgrading Platform Designer file "User/IP/serial_lite_iii_stratix/serial_lite_iii_stratix.ip"
Error(11133): IP component altera_sl3 with file "User/IP/serial_lite_iii_stratix/serial_lite_iii_stratix.ip" upgrade failed
Error(23031): Evaluation of Tcl script c:/intelfpga_pro/23.2/quartus/common/tcl/internal/ip_regen/ip_regen.tcl unsuccessful
Error: Quartus Prime Shell was unsuccessful. 43 errors, 72 warnings
Error: Peak virtual memory: 453 megabytes
Error: Processing ended: Tue Oct 31 20:49:51 2023
Error: Elapsed time: 00:11:19
Error: System process ID: 27696
Error: Peak virtual memory: 453 megabytes
Error: Processing ended: Tue Oct 31 20:49:51 2023
Error: Elapsed time: 00:11:19
Error: System process ID: 27696