Yooo fitness geeks! How do you count the calories burned?

I tried to google calories burnt by occupation (plumber) and physical activities (Muay Thai and gym). By what I've googled, these activities roughly add up to 1800-2k calories to consume, wt actual f. I struggle to consume my current goal of 2100 calories. by the way I'm trying to lose wieght and this doesn't sound right. Please tell me I'm doing this wrong.

6 ft tall, male and 200 lbs (not fat just American).
Yooo fitness geeks! How do you count the calories burned?
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