Here's a thread on the Framework forums where people spent years talk about how to get HiDPI working: https://community.frame.work/t/tracking-state-of-hidpi-on-linux/8301

Granted it's a few years old now. Last time I tried HiDPI was a few years ago as well. I definitely had lots of little annoyances. The blurry fonts don't bother some people, so maybe it's fine. idk.