I went down this route in the early 2010's. In preparation for an over landing expedition I wanted to have mechanical knowledge to be a sort of "mechanic" on the trip so I bought a bunch of "project cars" and began tinkering. While it WAS a lot of fun and I feel smarter, it was a total waste of time.

To save you all the trouble of all I went through, it was fun debugging mechanical stuff, but ultimately there is no "self-reliant car owner"

It all comes down to tools and parts. You need easy access to a lot of both or else you are limited to extremely ugly temporary fixes which amount to super gluing your engine back together.

On our overland trip, when we had an issue, it turned out impossible to fix without a massive lift and air tools, so all my years prep was essentially reduced to having a few extra words I could tell the actual mechanic capable of performing the fix.

If you still want to go down this route I recommend the book "zen and the art of motorcycle maintenance" and have 4 Saabs you can have lol. I'll even throw in the clutch kit you can't install without a custom Saab tool.