Maybe I should think about moving my Macbook's operating system to Linux. I keep running into such problems like above with the, by now 8 year old operating system that is no longer supported by Apple.
Updating it would be possible to a certain, also not current version. But I don't want to make the required change in the drive format that comes after my old version 10.13.6. And anyway, I'd lose a few apps which wouldn't run on a MacOS newer than 10.13.
This machine itself probably runs just fine for another 3-5 years.
Would be grand to avoid buying new (or 2nd hand) earlier than necessary.
So if I lose those old apps anyway, I maybe prefer to get used to Linux and to the apps on Linux rather than falling into another proprietary OS trap.
And a small partition on the side can still be reserved for MacOS 10.13 – if not even simply starting it as a Virtual Box directly from a Linux-booted system.
I haven't heard of Linux-ifying a Mac before. Heard of #Hackintosh of course, which is the other way round, turning a non-Apple device into a Mac . If that works with all the drivers for audio, network and stuff, it should work in the opposite direction as well.
Hope the process is not too involved. My poor brain can't handle solving self-created computer problems...