Is the Kings Gambit still good in 2020-2021?

The King's Gambit is very playable, but you really need to know your stuff with either side.  The main issue is that black doesn't have to accept, and according to Nimzowitsch, black shouldn't accept, as the capture takes black away from the center.  Of the lines where it is accepted, I find Breyer's variant (1. e4 e5 2. f4 exf4 3. Qf3) to be the most dynamic for white.

The Queen's Gambit is not a true gambit, as white can win back the pawn, but like the King's Gambit, black should not accept it, as the capture moves away from the center.

FizzyBand do you never tire of being completely wrong about openings? What is it with you and openings? 

The expression "and x is just better" is used when something is clear and obvious. There is obviously not a clear and obvious 1-move refutation of the king's gambit or it would have been noticed hundreds of years ago. So that is a ridiculous statement to use there.   

The King's Gambit is only bad for playing against people with an encyclopedic knowledge for how to refute it (opening knowledge and technical knowledge), I'm talking IM or higher. It is otherwise a fascinating and very deep opening. It continues to do very well at the lower levels, ie. around candidate master and below. It's a fine choice that gives white a good advantage for these players, the statistics prove it. There are plenty of openings like this that are a lot better at different levels, for example the Sicilian and King's Indian do very well at lower levels while super gms are finding them wanting these days. How good an opening is is a function of who will play it and what they know. Keep in mind also that even if the Schallop defence has been proven as better for black even for lower rated players, amateurs will likely continue to play the same way for many more years instead of hopping on the latest opening theory. 

The kings gambit is not what it used to be. It's probably not losing for white (not sure), but if black knows what he's doing then white will generally end up worst out of the opening.

you mean theoretical? Yeah

The answer to the main question of this forum is "no"

Exactly. And while the GM will know what to do in those positions and know them all by heart the amateur who rolls his eyes, sighs smugly and says "oh lord, the king's gambit's been refuted for decades" won't have a clue how to play them.  

The Kings Gambit is a gift to Chess. Play it, enjoy it. Don't feel bad for the naysayers who want to tell you how busted it is, remember they are all Super GM's whose genitals engorge at the thought of 35 moves of Ruy Lopez theory. Nothing says "I'm having fun" like attempting to grind down the Berlin defence. I'd rather take the -0.5 as White and enjoy the rich tactical positions the Kings Gambit offers.

The king's gambit is not completely trash. The bishop variation or whatever it's called is legit. (E4 E5 f4 exf4 Bc4 dis is what I mean)

I don't play it......the king is just too open bcz of moving the f pawn...

I've played over 500 games of 1.f4 and moving the f-pawn isn't so bad

and they say chess.com ratings aren't inflated.

if anything ratings are deflated. my friend took chess lessons, I beat him 90% and I thought he was intermediate. but when I played chess.com my rating started at 500

They used to objectively be deflated, at least in blitz. About 7 or 8 years ago many people reported their blitz as significantly under their OTB rating and some guy worked out in a spreadsheet after a major survey that blitz ratings were slightly lower here than a person's OTB rating. Rough approximation but I would say back then about 1700-1800 would be about 2000 now. This was reflected at the upper levels as Hikaru as the number 1 player was only in the 2900s or just about hitting 3000 and now he is over 3200 while plenty of players are at 3000. Even I can hit 2000 now lol. 

If Fizzyband was actually 2400 he would be international master standard LOL... considering his lack of basic understanding of some openings he is certainly NOT international master standard, maybe potential of being a candidate master.

I use it often with only moderate success. Players above 1100 usually dig it out pretty good. I'm not sure how useful it will be going forward.

Kings Gambit is my go to opening I have a good win rate with it. But of course I'm not going to play it against a much higher rated player than me, but people around my rating I have fun playing it. And that's what chess is about! just pick an opening that you enjoy!