Cardio+low cals day1/Lifting+protein day2? WILL IT WORK?

Do some reading on recomping and calorie cycling if that's your goal. I'll add that you still need protein on your rest days, so it doesn't make a lot of sense to me that you have high protein days and low protein days. Your protein needs are based on your lean body mass and they are basically static day to day - you don't need more on lifting days and less on rest days. That said, if you're over 20% body fat, I would probably continue to cut to around 20% before starting your recomp.

I am 6'5 and 320lbs (obese). I do know how to lose weight because I have done it before in competitions and was very successful, but when the comp. was over I gain it all back (so ig not very successful). I want to lose it permanently, but also gain muscle mass. I have always heard that turning fat into muscle is easier that starting from nothing. I have all the tools necessary to lose weight and to build muscle except the knowledge on how to do both at the same time.

Do some reading on recomping and calorie cycling if that's your goal. I'll add that you still need protein on your rest days, so it doesn't make a lot of sense to me that you have high protein days and low protein days. Your protein needs are based on your lean body mass and they are basically static day to day - you don't need more on lifting days and less on rest days. That said, if you're over 20% body fat, I would probably continue to cut to around 20% before starting your recomp.

I am 6'5 and 320lbs (obese). I do know how to lose weight because I have done it before in competitions and was very successful, but when the comp. was over I gain it all back (so ig not very successful). I want to lose it permanently, but also gain muscle mass. I have always heard that turning fat into muscle is easier that starting from nothing. I have all the tools necessary to lose weight and to build muscle except the knowledge on how to do both at the same time.

Take it for what it's worth, but my advice at 320 lbs is to cut and continue lifting while doing so. Make sure to hit your protein macro every day. You may even find you can continue gaining in strength while cutting, at least for a while, but focus your sights on retaining muscle mass until you hit a reasonable body fat percentage (say 20% or so). At that point, it may be more appropriate to try a slow and steady recomp to lower your body fat percentage while adding some muscle, but I think it's probably a bit premature to recomp at this point.

You say you've put the weight back on in the past, so keep in mind while you're cutting this time that it doesn't end once you hit ~20% body fat. If you switch right back to an aggressive bulk, the excess weight will of course come back.

It is scientifically impossible to turn fat into muscle. You cannot turn one kind of cell into another kind of cell. (If you learn how, though, let me know, because I'd like to try that alchemy and make some lead into gold while I'm at it.)

It IS possible to build muscle while losing fat. You have to stick to a very strict diet in order to accomplish that, however, and lift heavy and consistently. You should eat a caloric deficit (200ish calories UNDER maintenance to lose weight) while hitting the appropriate macros. Macros= fat, carbs, and protein. There are macro calculators available online (I've used the tools at bodybuilding dot com) for free that can assist you in finding the right macros for your goals.

Building muscle will help you maintain your weight/size once you have lost fat, because muscle burns more calories than does fat. Many people who fail to build muscle while attempting to simply "lose weight" regain the pounds they lost when they cease "dieting", because their bodies no longer require as many calories to maintain their weight. The most effective way to lose fat and keep it off is to lift weights and build muscle on your frame.

It is possible to build muscle while losing fat! I'm glad I'm not the only person here that realizes this. However, you don't "need to stick to a very strict diet". That type of thinking may set you up for failure, as you mentioned you have struggled with gaining weight in the past, when competitions are over. Eating to fit your macros never ends.

The only thing you need to do is get a tight grasp on what your daily macro/micro needs are. Once you have a full understanding of what your numbers are, then you can make dietary changes to hit those numbers, in a way that works for you. Some people struggle with the idea of being able to eat a flexible diet, and still meet your macro/micro goals.

Agreed, actually. Semantics. Adhere strictly to your macros=adhere to a diet, in my words. Just be consistent and STICK to it.