Very good write-up. I started playing Magic in late February and I've managed to hit Mythic 94/95% in both seasons I've played so far, and the best advice I can share from this post is definitely to learn the metadecks. It's really easy to tilt and say "oh of course he has fucking thought erasure" until you realise the person probably plays four copies of it.

Also, if you're losing perhaps try switching your deck up. The meta is the meta for a reason, so I'm not telling you to create a Grunn, the Lonely King brew when your mono-blue isn't working. Just maybe you aren't suited for that deck. Maybe patience isn't your strong suit so a deck that tries to control the tempo through counterspells isn't correct for you, and a more aggressive deck like monoW or monoR would be better.