Whenever I have a rear shifting problem that doesn't respond to shift cable tension adjustment, the first thing I do is to check derailleur hanger alignment. Most of the time that turns out to be the cause of the problem.
With a 7-speed cassette, I can usually eyeball the alignment adequately accurate. Shift your derailleur into a gear combination that makes your derailleur arm hang nearly straight down. Now prop your bike up against something and look at the derailleur arm from the back. If your derailleur arm seems to be leaning toward the rear wheel - that's it. Bend it back so that it points straight down and you'll be good to go.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.