I'm pretty sure a majority of weapon nerfs were due to mnk being too good. Ie. Lancer, Boltok, Marksa, Snub (idk if they were nerfed during Gears 5 but they are definitely toned down from Gears 4)
Bro, I saw your channel just now and I really liked it, I play on the controller and also on the keyboard and mouse, so I'll give you a tip, put the mouse scroll down or up together against the wall Along with the space bar or just the scroll, to make your movement faster and be able to do a cleaner wallbounce, otherwise it's great, much success to you bro