Intermittent Fasting - How Many Days Per Week?

I'm currently cutting. I lift on Mon Wed Fri and I do steady state cardio on Tue Thu Sat. I started intermittent fasting last week and I found it very easy to do on my cardio days - I was able to fast for 20hrs and then run for 1hr. However, I couldn't lift very much weight. On my lift days, I felt anemic/weak and completely depleted.

Q To get the most out of IF, should I continue lifting during the fasted state even if I can't lift very much? Isn't this bad for muscle growth?

Q Can I still get the majority of IF benefits if I fast on my cardio and rest days and then eat on a "normal" 3 meal schedule on my lift days?