Is there some place where we can request competent authors to update 1.12.1 addons to work for classic?
Yes please.
https://www.wowinterface.com/forums/forumdisplay.php?f=6
https://discord.gg/J9VUQ5g
https://wow.gamepedia.com/Porting_older_addons_to_Classic if you want to try it yourself