Hi,
I had the same Issue. For me the Eval Kit was quite useless without that IP core. I found the following temporary "solution" in https://community.altera.com/discussions/ip-and-transceiver/replacement-for-sdram-controller-after-v16-1/52218
Copy the IP core from an Old Quartus ( I think the last version where this core was supported is 18.1) version to the new Quartus version. /ip/altera/sopc_builder_ip/altera_avalon_new_sdram_controller
Additionally you need to modify the ip/altera/altera_component.ipx file. You have to add a few additional lines to that file.
</plugin>
<component
name="altera_avalon_new_sdram_controller"
file="sopc_builder_ip/altera_avalon_new_sdram_controller/altera_avalon_new_sdram_controller_hw.tcl"
displayName="SDRAM Controller Intel FPGA IP"
version="20.1"
description=""
tags="AUTHORSHIP=Intel Corporation /// INTERNAL_COMPONENT=false"
categories="Memory Interfaces and Controllers/SDRAM"
factory="TclModuleFactory">
<tag2 key="COMPONENT_EDITABLE" value="false" />
<tag2 key="COMPONENT_HIDE_FROM_QUARTUS" value="true" />
<tag2 key="COMPONENT_HIDE_FROM_SOPC" value="true" />
<tag2 key="ELABORATION_CALLBACK" value="elaborate" />
<tag2 key="INSTANTIATE_IN_SYSTEM_MODULE" value="true" />
<tag2 key="SUPPORTED_FILE_SETS" value="QUARTUS_SYNTH,SIM_VERILOG,SIM_VHDL" />
<tag2 key="TCL_PACKAGE_VERSION" value="12.0" />
<tag2 key="VALIDATION_CALLBACK" value="validate" />
<documentUrl
displayName="User Guide"
type="OTHER"
url="https://documentation.altera.com/#/link/sfo1400787952932/iga1401314928585" />
<documentUrl
displayName="Release Notes"
type="OTHER"
url="https://documentation.altera.com/#/link/hco1421698042087/hco1421697689300" />
</component>
<plugin
name="altera_avalon_new_sdram_controller.qprs"
file="sopc_builder_ip/altera_avalon_new_sdram_controller/altera_avalon_new_sdram_controller.qprs"
displayName="altera_avalon_new_sdram_controller.qprs"
version="0.0"
description=""
tags=""
categories=""
type="com.altera.sopcmodel.util.IElementPresetList"
subtype=""
factory="PresetFactory">
<tag2 key="PRESET_TYPE" value="altera_avalon_new_sdram_controller" />
</plugin>
These entries are taken from the old altera_component.ipx
This worked for me in Quartus 23.1 Lite