Hello🙂 I am an official coach, so I can help you with it. If you are interested in learning chess from a Fide Master, you can check my profile, write a message and we can discuss the details. 🙂
Playing chess for 5 years still has 300 rating
Try to choose simple opening, which you will play most of time, to have less complications. Maybe Italian game? Thanks that you will have more time for next moves. And learn basic mates. Look at my stats. I started from ~600 blitz
Learning openings is the last thing a 300 Rated player should do. I once saw an estimate that an engine which makes a random legal move every move has a rating of 261! If his rating is stuck at 300 then there is something seriously wrong with his gameplay and openings aren't it.
Yes. Correct.
How to play good chess?

Learn all the traps and do lots of tactics, you'll see that you'll have better pattern recognition and you'll be winning games in no time!

I don't think your opponent is tough. I saw your games where you both were making a really bad moves. You should analyze your last game using any chess engine. It will tell you the wrong moves you made. Remember it and don't repeat that "bad move" again with some other opponent.

If you want to get better, you need to focus on playing longer time controls. This is a recommendation I make (amongst others) in my most recent YouTube video, "Road to NM" If you're interested in educational, instructive chess content, subscribe to my YouTube channel to get notified about the latest videos. Here's the link:
https://www.youtube.com/channel/UCpRYz_ElTJC-FUq4unehOfg/
how to see upcoming checkmate my opponent do to me? I don't see my checkmate either . The game ends and tell u checkmated the other opponent. I castled and move the king pawn as I studied but it didn't work.
https://www.chess.com/live/game/4940492073

Play like kaprov, when your opponent makes a move ask "what is my opponent thinking?" so think of you opponents plan not only yours.

I have played over 1000 games and am still under 1000 in all game types. This may be unpopular, but I would argue that there is fundamentally nothing wrong with having a score below 800, as long as you have fun. When I tried to improve beyond about my current rating, chess stopped being fun and started feeling like torture.
If you want to improve for the sake of improving, then by all means do so and disregard this comment. But you shouldn't feel like you *must* improve or else something is wrong with you. Do what is most fun for you. Chess is a game.
It has been said already ... at first focus on playing longer time controls.
If you like we can play unrated daily matches and chat about our moves. We won't need one day for a match - that's just for the chat and our analysis. I'm not a chess teacher, but nevertheless such matches could help you to improve. Otherwise take lessons from an official coach. Good luck!

Analyze every blitz you play. Frame a setups for you each play. Practice it well. I know it’s easy to say and hard to do but when you follow the best moves on analysis of the game the you will be soon 1100+.
for eg. this pattern is mostly used by me same can be done with black.
Hey I want to leave chess forever . Can you look at my last 2-3 games and tell me that am I improving? Because I don't think so. In last 4 years after many puzzles and apps I don't think it's working for me. It's not losing but the problem is all the players like 500 rated players checkmate me like a very good player. Why I can't do this thing.

That's funny !!!! Keeping a rating of 1000 plus is not easy
Yes it's not easy for all. But possible...

Hey I want to leave chess forever . Can you look at my last 2-3 games and tell me that am I improving? Because I don't think so. In last 4 years after many puzzles and apps I don't think it's working for me. It's not losing but the problem is all the players like 500 rated players checkmate me like a very good player. Why I can't do this thing.
C'mon don't say so. For truth I really see no improvement in your last 2-3 games. But it builds up.
I saw your game. You take less time in moving. Also you are defensive more than attacker.
Take much time to move either you lose or win, try to think the best move. Still if you want to leave chess, the no one's forcing...
My opponent usually come up with his queen and either Checkmate me or kill my many peices. How can I do that?