Chances are it isn't the transmission. Have you checked the transmission fluid? I've seen them dirty enough that it made shifting nearly impossible.
If that is good, have you removed the boot on the shifter and inspect the shift tower to see if anything has come apart or if there is anything worn as far as bushings? (See pic 1)
If not, that is where I would suggest starting. Try this and let me know what you find. Additionally, if you have the boot removed, take a few pics and upload them for me to see.
Take care and Happy New Year.
See pic below.
Saturday, December 31st, 2022 AT 7:22 PM