Most of mine I just move around with Syncthing and I use either the Firefox saving plugin (Timimi) or the iOS app Quine, to view/edit them.

One of them I host on Tiddlyhost, a tiddlywiki hosting service. https://tiddlyhost.com/

The modern Tiddlywiki, TW5, can be run as a node app instead of a single file. Like, you can decompose an existing single-file wiki into a node app, or you can save the node app as a single-file tiddlywiki, seamlessly. So you can just run the node app behind nginx. That leaves open the problem of privacy though – you could handle that through http basic auth in the nginx server. https://tiddlywiki.com/static/TiddlyWiki%2520on%2520Node.js.html

There’s also a whiz-bang super-cool thing called “TWBob” which is a webapp which can host multiple tiddlywikis and do authenticated multi-user editing (!). I’ve used it in the past where I had a wiki I needed multiple people to be able to see and edit in real time. https://github.com/OokTech/TW5-Bob

Do you know whether your tiddlywiki is tiddlywiki “classic” (as the original is now called) or tiddlywiki 5? That makes a difference, classic doesn’t have nearly as many options as 5.