Converting Garage to ADU

It's a big bitch. Granted I will make the king bed a murphy bed. Obviously won't be a full sized kitchen and will have smaller appliances

What the hell is an adu?

convert it into a game room/man cave?

Not sure where you are located, but zoning may come into play.

If you are in an area zoned for single family, what you are describing is illegal. Doesn't matter if you are calling it a mother-in-law suite, granny flat, etc., you are effectively creating a 2nd living unit -- a detached (or attached, depending on whether your garage is attached or detached) apartment on your lot of record.

Again, it all depends on where you live and what you are zoned as (assuming there is zoning in place). Here in Jefferson Parish, though, that would be illegal, and the threshold that makes it so is permanent cooking facilities. You can build a pool house with separate rooms, a full bathroom, sink, refrigerator hook-ups, laundry hook-ups, all that stuff, but the moment you put in a cook-top or set up for a stove/oven, that's a no-no.

"It was here when i bought the house"

I will never sell. It's a three story home in Tampa on the water. Bought it before the prices went insane and my interest rate is 2.7%. VA loan with 0% down

If its on the water in Tampa it probably ain't allowed by code.