Been working on my fitness app for a while now, and it's getting some traction. But I’m kinda hitting a wall when it comes to scaling. Servers are more expensive than I thought, and I’m not sure how to optimize. Has anyone faced this and have any tips or resources …

Totally agree. Seen too many good concepts fail because the UX sucked. Hotjar is another good tool for seeing where users struggle. Don't skimp on this, it's worth every penny.