Your performance drops are the result of electrolyte imbalance and carbohydrate depletion.
Muscle is gained and lost in grams per day. Put bluntly: you don’t have enough muscle for “muscle loss” to be impacting you at only 6 weeks of fat loss. You’re simply employing a poor nutrition strategy. Most likely: too aggressive, paired with too much training, in an attempt to speed up the process.
As you’ve observed: your own instincts work against you in the pursuit of physical transformation. Most likely, you’re going to need to do the things you don’t want to do to achieve the results you DO want to have.