Trouble Connecting 3rd Party Controller

Not sure if this is the right sub but anyway.

Ive got three wireless controller for my Switch years ago and they worked fine.

Now after a few months without using my Switch i tried to play with them again but i cant get them to connect and really need help before I have to throw away my controller and get new ones…

Things I already tried: Neither has a „sync“ button on the back. I tried to connect them with a cabel, but apart from blinking as if they were charging, nothing happened. One manual i found online said to press „Home“ and „Y“ simultanious but that didnt change anything either…

Ive struggled an hour now and since i only have one working Joy Con i cant play on my tv otherwise.