

There is always emacs with org-roam.
Org-roam is kind of a wiki, you write your notes with all the formatting power of an org-file and you can link to other notes you have written.
Of course everything is searchable, with tags, without tags, however you want.
BUT: it takes time to get used to the shortcuts, and it takes a lot of time to configure everything how you like it.
The result is worth it.
Edit: I use Nextcloud to sync my notes accross my devices. On the smartphone there seems to be the App OrgNote available, but I haven’t checked it out, as I don’t use my smartphone that much.
Unreliable search, can’t handle one online and one local postbox side by side (both have to be turned to online postbox), it messes up my contacts every chance it gets, rules don’t work on the online postboxes,… And everything is so slow!
I am so happy with my Linux setup, but for this one costumer I have to use this shitty piece of software.