No problem in depending on CapRover, as long as you are at least somewhat familiar with the tools it sets up for you. Combine that with some crude generic UNIX skills (quickly analyze cpu/ram/disk usage, search in logs, transfer files, modify configs etc.) and you're way better prepared.
Ironically it's best learned "on the job" (for me at least); just try to deploy your app from scratch. Play around with nginx/apache, letsencrypt, your db stack, packages installation etc. and get a working product.
I'm no expert by far in any of this, but think that knowing "just enough" about these tools really helped along the way. Up to the point where I can now use CapRover like tools with some degree of confidence, closing the full circle ;)