How to disassemble Harden (Symmons) tub/shower valve trim?

I’d like to replace the old Harden tub/shower valve trim in my condo’s bathroom.
As far as I know the Harden company (which already went bankrupt) only made trims and they used Symmons hardware under (i.e. valve, etc.).
I’d like to put a newer Symmons trim on (e.g. S-6700TS-TRM).

My issue is I can’t take the knob off from the shaft.
I tried to use strap wrench for that but it wasn’t successful, maybe I needed to put more force but I’m not sure and I didn’t want to damage the valve.
I also applied WU-40 spray between the chrome (smaller) and the copper (bigger) knobs before that but it didn’t help.

Can somebody who is an expert please tell me whether the chrome (smaller) knob should be turned clockwise or anti-clockwise to release, and explain how this valve trim should be disassembled?

Thank you!

Peter