Chess Explanation?

So I haven't played chess since I was a kid and I'm trying to get back into it. I played as white and the last movie was played by black where one of my queens took their bishop. The game auto-ended right there calling it a draw! I don't understand how that would be a draw. Can someone please explain this?

my friend dared me to change my flag to north korea and I got this after a win, am i doing this right?

Why is this move a miss?

Black’s knight is preventing my rook from doing a mate in one and it’s being attacked, neither of its escape squares can help it defend my rook’s attack and black’s bishop can’t take my knight because it is pinned to the king.

Black has forced mate

Glad I saw that in game, opponent was up by +6

I finally beat Antonio!

Screw stalemate. All my homies hate stalemate.

White to play and stop black's attack

Lol I found this

Huh

How do I avoid losing games from positions like these?

I primarily play 3|2 and fluctuate between 500-600 rating. I find myself dominating a lot of my games yet miss out on clear checkmates quite frequently. What can I do to work on this?

Why was this move brilliant?

I was playing a bot and made a brilliant move but don't understand why it's considered brilliant. Can someone please explain?