2013 jku Sahara 6 speed, when I shift from 1st to 2nd sometimes it grinds and sometimes it goes right in. I’ve tried it at all rpms and speeds and same issue. It tends to be worse when slow wheeling in 2by. All other gears shift just fine...... y’all have any ideas I’m thinking shift fork is bent or synchronizer is going out

Sounds like the synchro has been ground down from your description. Those teeth get worn down (see pic below) if there’s too much grinding when shifting incorrectly. I’m no transmission expert. Suggest taking it to a reputable shop and have them give it a look.