So cheap... update 07/19/22
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Remember that cheap  ATU100 EXT antenna tuner I tried  out for $37[1]?
Figured I better give an update.

It arrived in a reasonable amount of time. It looked perfectly fine. I
took the cover off and examined  the innards--mostly just to verify it
wasn't an empty shell. Check.

It powered up and held a charge. Check again.

Find  a  crappy  "manual"  online   (crappy  in  the  sense  of  usage
instructions, not technical details. People  build these from kits, so
lots of details  are out there, but not a  clean, simple users manual.
Anyway, I determined that it was dead  simple to use: one press on the
only button would reset  the tuner, a long press would  put it in TUNE
mode. Both "RESET"  and "TUNE" would appear on the  screen, along with
other details when it was working.

Tried it out with the G90... and nothing. No response to the RF in. No
attempt to tune.

Searched around online and found a  video of another person trying out
a  similar  cheap unit.  They  described  a  problem with  the  SO-239
connectors being loose and of low quality. By loose, I mean the center
pin hole comes out. Sure enough, mine had this same defect.

While examining things,  I also noticed that there  was some shielding
missing inside. I put that in place, and soldered on some nicer SO-239
connectors...  and  presto! It  started  working.  I've tested  it  on
multiple radios across bands  from 80m to 10m, and it  seems to do the
job quite well.

So, while  not an off-the-shelf  item, it wasn't  too hard to  make it
serviceable. And  since it's a ham  radio item, I guess  I really can't
complain that I had to do some soldering. Especially for $37.

[1] gopher://zaibatsu.circumlunar.space:70/0/~tfurrows/phlog/2022-04-26_soCheap.txt