Try to figure out where the issue could be.
Did you try using other joy-cons, and did you try connecting the joy-cons to another device like your PC through bluetooth?
Do other wireless controllers work (e.g pro controller or 3rd party)?
I may try the new ram site, and download more RAM to my Switch. Not sure if ddr3 is the right ram
for it tho. Edit- no it uses floppy Ram, just like @AncientBoi