This is my main wiki software nowadays. I use it for organising my thoughts plans and projects. It has a lot of extra addons that I have tried out. The ones I've found the most benefit from are, Slides Extended, Homepage, Calendar, Dataview and Tasks.

I have used Tiddlywiki in the past before. As everything is kept in the same html file, it makes source control very easy, but it makes it impossible to collaborate between multiple people. It also begins to slow down quickly, the bigger the wiki gets, and you can feel it barely holding together. I would personally not recommend Tiddlywiki.

I used to use this, but nowadays I don't. I personally think Obsidian is better if you need to record information that has images or anything else of the sort.

Additionally vimwiki also makes it difficult to do notetaking across

Werc can be used as a bit of wiki software. If you consider my website to be more of a wiki, I suppose it is then!

This is more of a source control tool, though you can set up scripts to automatically push and pull from it occasionally. I would recommend using it for backups, but less so for synchronising across multiple devices.

Unless you're technical I don't recommend rsync. It is more of an FTP file transfer tool and you'll be making a house of cards by gluing rsync together to sync between your phone and your PC. I do use it for any file transfers to my VPS though.

I primarily use syncthing to synchronise my wiki between my phone and my PC. As Obsidian has an (ad-free!) app, this makes its use seamless.