Excellent suggestions. Any one of them would be helpful -- all would be tremendously helpful. Thank you, Sarterus.
Tactical Trainer Review

But there's a big disparity with his other numbers.
My thought is that tactics training is easy and satisfyingly direct but it doesn't translate that well into actual chess strength.

Well, it's not just that - it's the fact that when you get repetitions, you get free points.
I've done only 260 tactics total, and I've gotten a couple of duplicates, that I answered quickly and got a few points for free from.
This guy's done like 10000+, so I'm pretty sure he's gotten hundreds and hundreds of duplicates at least, if not thousands.
Compared to his other ratings, his tactics rating is about correct, given how many attempts he's made.

I think I'd get a lot more out of spending hours and hours playing over the instructive games of Anatoly Karpov if I was actually interested in improving.

You're right! At the higher levels, tactics trainer gets a lot of diminishing returns.
But if you're a beginner, you'd be better off repeating tactics over and over rather than looking at GM games.

when I began my rating went up 100 points immediately after I took a one hour endgame video course (Chessmaster I think it was), and that was the fastest bump I ever got by far

Beginners should study CHECKMATING patterns until they have them down cold, and play over classic games.
I hate it when people pass up checkmates.
THIS IS THE OBJECT OF THE GAME, PEOPLE.

And you can see how they arose.
The idea behind TT presumably is that you get the nifty stuff in concentrated format, thus saving you time and effort.
Think about it!

Anybody can learn chess notation and enjoy instructive games that were played 200 years ago. That's a big part of the beauty of chess.

"Treat with an apparent kindness that betrays a feeling of superiority"
That's not accurate?
I should have said I won't insult them?
I defer to your expertise as a native English speaker. I'm only an American.

Where is the tactics trainer? I've been trying to find it everywhere.
Just means the puzzles https://www.chess.com/puzzles/

I do 26 puzzles every day (allowed by Gold membership) and allow around 1 hour.
I like seeing the timer to inform how much time I have spent but I had never registered that the small clock shows the expected solve time; I thought that it was simply a timer running animated icon. Now, I can't unsee it
It would be great if it was possible to see the elapsed time but not the 'difficulty' indicator.
Summary of advice:
Summary of improvements needed: