Lower your bias and see if it’s still ice. 65 70 is too high for a fender. Try 50 and see if it gets warmer. That 60-70 rule is not always the rule. I have fenders that are running at 45% .. anything above 60 and they stop sounding like fenders and they start sound like azz.I compared the non-reverb amp with the reverb amp normal channel again.... and they actually sound very similar. It seems you're spot on here. I think I'll just accept the reverb channel for what it is and let it be a bit bright, icepicky. Turns out they invented this thing called a tone knob on the guitar.
Also, try a variac. Drop the line voltage down like when they ran gz34s… or just stick a 5u4gb in it and call it a day.