[morzh]

Today the 10 Ohms resistors came (It might've meant in the sch it was 10 ohm total), and soldering them in improved things a bit.
I wiggled the originals and one of them does show fluctuations in resistance.
The hum periodically produced some more buzzing sound.
I looked in my stash and found a couple more of 47 tubes.
Checked them, both are nice.
Re-checked the one from this radio, and it is fluctuates: the value goes up to 1,200 and then goes down to like 700 and back, slowly...not so with the other two.
So, I put them in one by one, and that periodic buzzing component went away.

I unsoldered the voice coil and connected an 8 ohm (yes I know) speaker to it, and heard the same quality of sound with the distortion on the lower spectrum of music, which I was trying to figure out, if it could be attributed to the cone repairs. Nope. They could not.

Then I decided to turn on my 82 I repaired 2 or 3 years back.
I hear the same exact hum and the same exact distortion.

Actually, late version of 84 and the 82 are exact same radio, with AFC tube added to 82; Otherwise the sch is even drawn the same.
But the early 84 is also the same, with 24A tubes instead of 35. So, no wonder that they suffer from the same ailments.
(And 82 specifically says about the flex resistor "10 ohm TOTAL") which tells me that yes, the halves should be 5 ohm each. Not sure it matters much.

I will wait for a few days and, if I do not come up with a plan to tame the distortion, I will align it and be content.