Thanks anyway, Bruno. Since posting, I found my fix. Took several repetitions of some kind of forgotten Druid ritual for the 2019. No idea what triggered it, but solution involved holding power key down ten seconds to complete the power off (bizarre already). Then holding control and option and right shift key down together for 7 seconds… not longer, not shorter. Then also reaching up to hold the power key off, all four together for 7 seconds, then letting go all at once… then shutting the lid and reopening (not all sites gave that part). Then press power key.
I did that process repeatedly, unsure whether to have it plugged in or not. Last time I did the sequence, did it unplugged, then plugged it in, let it sit overnight.
figured I’d have to take it in (60 miles from home). But woke up this morning to a fully charged, perfectly functioning MacBook. No issues charging today. Charger works plugged into any port.
I know how to translate instructions from runes into English now! (Who comes up with this stuff?)