Should I transplant !?

Just don't let the soil n root ball fall apart which it can do without a lot of roots. If it does it will break roots which isn't good. General rule is that when the leaves pass the pots circumference it's time to do it. Don't if an auto. I like to fill bigger pot up with medium and the plant in its smaller pot. Then take out the plant, remove old pot and slide into the previously made slot for a perfect fit. Try add myco at this point. If done without disturbing the soil/root all then you shouldn't have any transplant shock at all. There are a few things we do that shock the plant but by doing them carefully and properly we can minimise or eradicate shock altogether. Another example is that when topping it can set it back days. If when you top you let what you are gonna cut grow a bit it won't skip a beat.

I would definitely transplant 👌🏽

Time to transplant give 3 - 4 weeks. but you can do it now

Sure. It’s not pushing the limit of root bound by any means, but if you’re planning to transplant go for it. Won’t hurt.

Yes some Mycorrhizae would help too. I would say few days later, but pot is occupied enough to do it.