to make your PS1 games look like they are running on a modern HD console?

You should technically own a physical PS1 console and dump your own BIOS to stay within legal "fair use" boundaries. Once acquired, place these files in the /bios/ folder of your ePSXe directory. Step 3: Enhancing Graphics with 2021 Plugins

: SCPH1001.bin (US) or SCPH7502.bin (European) are highly recommended for the best compatibility.