I hear you.
I was on Test E for a long time, about a year, I am one week switched to Test C on an EOD schedule but have lost a bit of muscle firmness and strength.
It’s concerned me so I’ve been trying to get as much data as I can.
My problem has always been not giving things time, I’m trying to give it a good month or more to build up but haven’t been able to work out since switching.
I do feel a bit calmer and happier though which is strange.
Have you noticed any differences in your E2 between the E and C?