How do you find your caloric maintenance?

Every website tells me something different, and I also think it is hard to know how many calories an individual burns throughout the day.

It wouldn't be a big deal, but I want to stay within a 100-200 caloric deficit for an extended period of time.

The only accurate approach I would have an idea to do is to weigh myself once a week after tracking calories and see if I gain or lose. But my activities change throughout the week, so what if I burned more calories one week and I think it's my maintenance?

My bro you're over thinking it way too hard. You got to understand that even when you calculate your calories you are never going to be 100% accurate, there is always going to be at least a 50-100 calories miss calculated.

If I was you bro I'd just keep weigh my self on a weekly basis and then over a 5-10 week period assess whether or not I'm losing weight. Remember your greatest asset is going to be a mirror bro, if you can visually see that you're getting leaner then you're on the right path. Don't let the calories control you, you control the calories.

Each site tells me something different, and I also find it difficult to know how many calories an individual burns throughout the day.

It wouldn't be much of a problem, but I want to be left with a 100-200 calorie deficit for a long period of time.

The only precise approach I would have an idea to do is to weigh myself once a week after monitoring calories and seeing if I gain or lose. But my activities change over the course of the week, what if I burn more calories in a week and think it's my maintenance?

I would weigh yourself every morning. More data is better than less when it contains 'noise' from day to day changes in water levels. You can't rely on a single weekly change being noise free.

You will never know your true TDEE and it changes every day in any case. You can approximate it over a period of time - you should aim to have typical levels or acticity in this time and weigh and measure everything you eat carefully.