Which reading would you recommend for a FIDE 20xx player to work on strategy?
ask a professional chess player anything

honestly I didn't read any books until I was a GM so I can't give you great recommendations. to work on general strategy and middlegames I like to study games deeply.

When you face an opponent who is rated roughly the same as you but you keep losing to them what do you do? This has been happening to me lately against an opponent and I've never had it happen before.

When will you become a professional chess player?
I have been a professional for over two years

When will you become a professional chess player?
I have been a professional for over two years
So you can beat Magnus Carlsen?

So what is your opinion of the King's Gambit, and as a more important question, how should one go about improving their Endgames (More than just elementary Mates)

When will you become a professional chess player?
I have been a professional for over two years
So you can beat Magnus Carlsen?
I can't tell if you are trolling or not

When you face an opponent who is rated roughly the same as you but you keep losing to them what do you do? This has been happening to me lately against an opponent and I've never had it happen before.
It's a psychological thing unless the person is just training a lot more than you. It takes time and there's normally some sort of mental barrier which must be overcome. Keep going at it- try to ignore the past and treat it like a fresh game. maintain your confidence they are only human

How do you study games?
Games of stronger players. I like to play through the moves and try to figure out why they played the moves. Even the easy looking moves normally have a lot of good reasoning behind them. No computer help. Try to put yourself in their head.

GM Hansen, thanks for availing yourself like this.
What do you think SuperGMs understand about the game that has eluded you thus far?

So what is your opinion of the King's Gambit, and as a more important question, how should one go about improving their Endgames (More than just elementary Mates)
King's gambit can be fun but it is not a top tier chess opening and it can be limiting to only play just the gambit.
Improving endgames is a matter of 1)improving calculation,2) playing many endgames, and 3) learning some theoretical ideas such as how to play rook endgames or learning something like knight + bishop vs king

how many official fide chess set pawns can you fit in your mouth
haven't tried that yet. I would need a chocolate chess set before I would try. I do have a big mouth
and...go! i'll try my best