depending on the person, but your daily caloric output is probably around 2,000 calories per day. give or take about 200. More if you workout or walk a lot.
If you’re not eating 3 days out of the week then you’re putting yourself at a roughly 6,000 calorie deficit (assuming on your feed days you are breaking even).
By limiting indulgence to just the weekend, imo it would seem difficult to indulge to the point that you undo that caloric deficit. Particularly without feeling completely sick. a pint of ice cream is like 1,000 calories for reference (depends on the variety of course).
Sure, eating more than you burn on your feed days is going to slow your progress. but if it helps sustain your fasting strategy in the long term, thats where the benefits come from. You’re a month in at this point. The gains are made from keeping this up over the next several months.
Edit: brain fart
aim for maintenance calories on your treat days, that way you dont squander any of what you lost during the fast. its so important not to overindulge during fat loss, as what takes hours or days to lose can be more than eaten back in minutes, even seconds depending on how calorie rich and addictive that food is. i would invest in a kitchen scale and get your maintenance calories sorted.