1) given when you started playing comp, competing in main/div 2 seems pretty fine. of course there are gonna be people who move up the ladder faster than you, but don't compare yourself to someone else today, compare yourself to you yesterday. I realize you're also worried about your lack of improvement, but keep in mind you also moved up vs better people, and a lot of it could be them punishing you for mistakes that went unpunished before.
2) much easier said than done, but get out of your own head. I've played against so many mge lord scouts that are terrible in game. sometimes it's because they have no gamesense, but a lot of the time it's literally them not coping with the pressure of hitting their shots in real games compared to a controlled practice environment. being mentally strong won't make you an invite player, but it absolutely does help with some of those 'beef' moments. it sounds like you also turn inward a bit when they happen and think about them for a long time, which is not healthy- focus on the next fight.
3) worst comes to worst, take a break for a week to refresh or spend it playing other classes. playing multiple classes will help you see the game from multiple perspectives and help skills translate over. also, and not everyone will admit this to you, if you REALLY feel like it's not helping, maybe a long term switch to soldier, demo, or medic wouldn't be the end of the world. if you're a high sens player who feels like your accuracy isn't improving, but your gamesense and comms are good, scout may be the class that emphasizes your weaknesses more than your strengths. that being said, I've also seen a lot of garbage scouts have everything 'click' and improve rapidly, so I wouldn't foreclose on that as a possibility either.