I didnt see any stickies with this info so I had a few questions. I haven't played tf2 in over a year and never was involved with the competitive community. I've played several other games at a high competitive level, and now I am interested in finding out where to start with tf2.

My main question is what leagues are played , and what configs are used? I imagine esea / cevo? The main thing i want to know right away is how to change my fov higher than 90, and if the unlockable weapons are used in competitive play.

Start in the TWL league and from there you can move onto ESEA and CEVO but surprisingly TWL is still the most popular league in terms of teams enlisted. I doubt you can change the FOV above 90 and I believe in TWL almost all unlocks are allowed. For configs just use your own because it is all preference, even network settings.
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Hope this helps.

If you run in windowed mode and manually set your resolution to an aspect ratio wider than 16x9, then the source engine will draw more than 90 degrees of FOV. E.g., I have "-window -noborder -w 1680 -h 900" in my launch options, which gives a slightly wider FOV than 90 (on a 1680x1050 monitor).

I think you can go into the console and type fov 100.00000 or fov_desired 100 but I haven't seen any difference although my fov is 90 so I imagine an extra 10 degrees wouldn't make much of a difference.

90 fov is the cap