I would never go with Samsung as a conscious choice for custom ROMs, mostly because all well-supported devices are pretty old, which means lower chance of getting something in a decent state for a reasonable price used, that wouldn’t require immediately swapping the battery already. Not to mention the Knox eFuse which means losing functionality when flashing a custom ROM. I’d argue a used Pixel is a better option, the 7 Pro can be had for relatively little money and is still a good phone.