Don't update to one ui 7 as you are telling that the device is heating much,wait for sometime and notice if the update is stable then go for it and oneui 7 update will start to rollout during the month of july

I am using m34 for more than 1 year i didn't faced any major issues the minor issues are network,the speaker issues, heating issue it's heating like a hell during outside usage but using it in room temperature the phone always stays warm