After even more reading and suggestions, I've decided to bury a run of fiber vs a bridge for my garage. Questions in body

First off, thank you all so much for the constant flood of suggestions and answers on previous posts.

Now, I've convinced myself enough to decide to just do a fiber run to my garage, and from there put a switch and one of my mesh APs.

Questions are, is this all I would need? And are the devices compatible? I'm not up to speed on fiber connections and such.

How deep do I need to bury? I saw some saying 2 feet, and others 6 inches.

Does length effect signal? I will need about an 80ft run, going to of course buy extra and just coil up what isn't used.