I definitely can commiserate with the frustration. I've got mine built to the point that I can see all the rough edges and all the things that I'd want to do differently.
I've busted one 50" tv already, broken mounts, completely re-worked the control pedestal because it was wobbly (because one of the casters was slightly off-level) enough that it wasn't stable for pinball, badly cracked the wood on the underside of my control panel because I wasn't paying attention, and that's just in the last couple of months. We won't talk about how bad things were when I first started
.
I work in IT, and I've been dabbling with emulation since the late 90's (Nesticle on my pentium 166 laptop when I was in high school!) so the 'computer' side of all this is the easy part for me. I had virtually zero woodworking experience going into this thing, and that's the part that has been the most challenging for me... but also the most rewarding. I made a lot of mistakes. I'm STILL making lots of mistakes. I've learned something every time though, and I'm getting better at this - I can actually see the difference in the work I do now versus the work I was doing at the beginning.
This will pass. You'll work through it. Your design is sound, and what you've done so far looks great. You're on track to have an amazing cabinet - just keep at it!