A Microsoft file hosting and synchronization service.
This 'solution' (well, hack actually) worked for me:
Steps are basically: download a previous version of OneDrive. Annoyingly, the download links in the article with the solution now all point to the new, 'broken' version, so you can't download it from there. Fortunately, there's a guy who has posted every single onedrive version yet:
https://hansbrender.com/all-onedrive-versions/#tabmac
There, look for version 23.054.0313.0001 and download it.
While you download, make sure you already open activity manager and force quit the Standalone Updater that keeps on aggressively rearing its ugly head like a digital groundhog. It needs force quitting twice otherwise it will not take the hint.
After download, if you cannot find the package file, look in your rubbish bin – the Standalone Updater may have already moved the installer to the bin. It really is Clippy's evil older sibling.
Switch off wifi to avoid any updates.
Then install the package. It will not do so by clicking on it, because it's an unsigned update, so you will have to right-click and insist it installs.
While installing, keep an eye out on the activity monitor to stomp down any attempts by the Standalone Updater or the OneDrive Auto-updater to disrupt the process.
After installing, go through the terminal steps in the article first, and THEN switch on wifi and fire up onedrive. Make sure it's the right version, though, by calling up the info on the app by clicking on it once and then hitting CMD-I. If it says 23.054.0313.0001 then it should work.
I am now enjoying my working older version, which is happily processing the many updates of the last days. I hope you will too!