People who use cloudflare are likely to have a hard life. You can search here and find lots of examples of how. Installing the template is just a piece of the problems you might have, and the easiest to fix. (I’d recommend that you use a real CDN like bunny.net which is cheap–but not free–and easy to configure, but that’s not what you asked.)
Of course, your issue had nothing to do with cloudflare, but the reverse proxy, so searching for cloudflare was likely no help!
Still, adding a few more stock templates like reverse proxy (and the one that I really want–one to precompile assets and push them to S3) is a good idea.
Good luck.