Just a follow up, I will switch to the File Renaming method for the time being.
I was thinking about this problem and to me, in a sense, linking files to filenames statically (in the sidecar approach) hinders the interest of using files in the first place.
If the tags depend on a filename which I cannot change otherwise they break, it may be easier to just embed useful information in the filename directly - and we come to the File Renaming approach.
I also saw that this topic I’m writing about has been around for longer in the forum - at least four years: Are sidecar files realy viable in practice?
Hopefully TagSpaces will come up with a way to deal with this shortcomings of the Sidecar approach. For the time being maybe the go-to advice is: use the File Renaming method.