Building your first build in a small case always leads to these kind of headaches. I'm not singling you out. But if you look at a lot of submissions, you'll see that people often fall into this trap on their first builds with a small palette or "skiff" type build. You're building a battleship in a bathtub.
-- Ronin1973
Its difficult to allocate $8000 to build something larger when you have no idea what you want or what you're doing. Hindsight is always 20/20 and this perspective is something that can only be gained by personal experience. The palette is designed to be accessible and lots of people employ them successfully.
-- drfear
A Mantis case is around $335. A Palette is $299 to $400. No one is saying to drop $8000 on equipment. What I'm saying is that you bought too small of a case for your first build. There's no flexibility in a space that small. But people keep wanting to buy super small cases and then paint themselves into a corner on the first build.
There's nothing wrong with your selections. There's nothing wrong with the amount you're spending. But you're going to have a hell-of-a-time getting a reasonable amount of features into such a small case, learn more about modular, then tweak your case to work better for you. You have no room for expansion.