Okay, but is it the fault of the monk that they received little to no support in feats and magic items (two "optional" sets of rules that are completely under DM control?)
Monks get the benefit of magic weapons just like any other fighter. They just need to be Monk weapons.
If the new UA on Alternate class features is anything to go by, then it looks like those choices will be expanding further for core Monks.
Personally I have no issue with 'monks robes' that add a bonus to hit and damage for unarmed strikes, grant an unarmed strike at 1d6 damage, and are priced at the same level as a magic weapon (requires atonement). It's a homebrew magic item I include in my own games. It's home-brew but I would love to see something core like that for Monks.
And if Monks lack 'feat support' (not sure I agree here) then that means they're going to have better ASI. Which translates to better bonuses to saves, hit, damage and so forth, Monks gain a lot from ASI's in any event via Dex (Hit, Damage, Initiative, Stealth, AC, Acrobatics) and Wisdom (Wis saves, AC, Save DC's, Perception, Insight) as it is.
My two favorite Monk builds are my Ninja (Shadow Monk that combines Assasin Rogue and Gloomstalker Ranger) and my Kensai (Kensai Monk that combines a few levels of Battlemaster Fighter). Admittedly they're both MC Monks, but they function just fine in games with feats and magic items, and with raging GWM barbarians, Wizards and Hexblades all over the place.