To the OP: you attribute this to your failings of age and you forget that this isn’t uncommon if you are an audiophile. If you find it difficult to crawl around and sort out a cable mess or noise within your system, you need to find somebody who is technically inclined, respects good equipment, and has a detective’s ability to find the culprit.
I’m in a location now which is not gear heavy- most of the techs in Austin Tx are about repairing instrument amplification, not hifi. Some of them are afraid of dealing with hi-ticket stuff and won’t do home visits. You need to find the "right" person, wherever you are. I found a guy only a couple miles away who was extremely knowledgeable of pre-WWII tube gear and ’78s. I was totally comfortable having him work on my more modern tube gear and system, which clones the pre-War era-horns, SETS, main source is vinyl, which didn’t really exist until later. You can get it sorted.
The question is whether this is too much bother. You won’t get much return on selling to a dealer and buying new stuff- people seem OK with retail Internet. Man, it was the casbah when I was in acquisition mode, and I didn’t have to "hondle" or negotiate. Find the right competent dealer (rare) and they can help without gouging you.
Did you say where you are, geographically? I think even NYC, which was at one time heavy with audiophile retail, isn’t what it once was. You’ll need to do some research and talk to some peeps wherever you are to find a solution to the immediate problems and a long term solution.
My long term solution is: I die, the crap gets sold. Period. The records are probably worth as much as the gear, maybe more.