I was having the known problem with Text Console using CTRL + ALT + F1-F8 bug of tearing / square pixelated screens.
I am currently still trying/testing with some options in /boot/loader.conf file to see if I can fix this issue of the tearing with Nvidia drivers 510.60.2.
after make installkernel I got a lot of messages
"kldxref: unknown metadata record 4 in file". But I have ignored that.
Then I do like it was described in the handbook:
mount -u /
mount -a -t ufs
cp -Rpv /etc /home/etc-170128
mergemaster -p but it has merged...