Currently suffering from multiple technical glitches with my dota, can anyone help?

Alright so some of these problems have been persisting for ages and others have only come up recently, if anyone has encountered these problems and found a solution then I would be very grateful:

• On Dota startup, my dota's brightness goes very dark even though my brightness is up full. The only solution I have found to fixing this is watching a game, in-game (very weird). I have also read that disabling steam overlay helps but I rely on it too much..

• Oh, sometimes if I go to watch a game, it gets stuck on the loading screen, and I can only view the slider at the bottom. The only way I can avoid this is by not being tabbed while I am loading the game and also by, believe it or not, moving my mouse around instead of having my mouse idle while it is loading. I have no idea why that works.

• Sometimes I alt-tab dota and I can not get back into it, simply will not let me open again, i have to close it from task manager and open it again.

• If I remove my audio jack while in dota, the entire game freezes and I have to ctrl+alt+delete and sign out, I am unable to do anything else, if I alt-tab my mouse cursor is replaced by dota 2's custom cursor and I can't click on anything

• Many of my friends, including me, have a problem where sometimes at a random point during a match I am suddenly unable to control my hero or press any buttons, even though the match is still going on around me. This could be attributed to packet loss but it seems a bit extreme

• This one isnt a glitch but my fps is quite low, around 40-50. Sometimes it drops to 20's. My video card is 'AMD Radeon(TM) R7 Graphics' and my CPU is 'AMD A8-7650K Radeon R7, 10 Compute Cores 4C+6G'. (I have no clue about this stuff so if someone could tell me if either of those are bad I'd be happy to buy a new video card/cpu)

P.S. If you actually took the time to read through these and help me, thank you sososo much, I have been having these problems for ages and its really stressing me out!