David wrote

Back in the day I worked from DIY manuals, including a very
good Readers Digest one. We are talking 1970s though.

These days most of the advice seems to be YouTube videos and websites.

Are there any real paper DIY manuals which are both good and current?

No idea, I find YouTube videos and websites much better
and much more likely to be specific to the problem you have.

For example there is some problem with the windscreen
washer bottle in my car and its in the wheel arch behind
the cover panels with no obvious way to get it out. There
us however a very decent youtube video showing you how
to get it out easily. No paper DIY manual will have that.