Hi Sir,
Since you are using the example design (ED) as a baseline, why not you follow the User Guide to generate the RX-TX re-transmit design then follow the step to remove the component for TX-only design.
I checked your HDMI/Native PHY IP setting, I found that for Native PHY, the data rate for ED is 6000 Mbps while you are using 3900Mbps. Maybe as a quick check, you can try to change the data rate to 6000 Mbps and try.
I summarize the suggestion as below:
1. Change the transceiver data rate to 6000 Mbps.
2. Generate the Tx-Rx design, remove the RX and other components as stated in UG. Integrate the customer video source and try.
3. If your board has the Rx channel, build the Rx-Tx design, connect Rx from external video source see it can re-transmit the video.
4. Connect the reset signal to a toggling button or ISSNP. So that you can toggle it when connecting to a monitor see if the display works after reset.
5. Upgrade the design to latest version, at least 19.4.
Last thing is how you determine the dmi_clk_in is 65Mhz? I generate the example design target Arria 10 development kit, the frequency is 300MHz.