We're gonna need logs and hardware info to debug this issue. Please let us know what hardware you're running, then do the following from 5.10 (you will need to switch over to a TTY via Ctrl+Alt+F1-F9)
sudo journalctl -b -e > journal-log
Then switch over to the "working" kernel and upload the contents of journal-log to hastebin.com, which will provide you a hastebin.com link (just changes your URL in the navigation bar when you click to save). Paste the link here alongside your hardware info.