There's a lot to unpack here. I guess I'll go in order.

## Everyone's game styles are different (in at least some amount).
I prefer more of a "Follow the rules as they are written" style. I also know that not everyone feels that way.

When I'm a player, I tell the DM that I'm going to point out something in the rules and answer questions. If there's a change to the rules, that's fine, just let me know and I'll mentally pack it away. 
For example: 
 > **Party member**: *How does healing work during short rests?* 
**Me**: *You can roll as many hit dice as you have, one at a time.* 
**DM**: *Goodguy ,actually, I feel that using all of your hit dice in a single rest is a bit too strong, we're only using up to half your hit dice per rest in this game.* 
**Me**: *Okay. Got it. Sorry about the confusion.*

No problemo. I've relayed the information that I know and then move on. This relationship has worked pretty successfully in at least 3 D&D 5e games. The only issues I've run into were *before* hashing this out with the DM in question.

When I'm a DM, I explain to the players (in session zero) that I try to follow the rules as a baseline and I might improvise special mechanics as needed. If I get a rule wrong in the middle of combat or something, note it and let me know about it later; we're not going to ret-con the past 5 minutes because you were able to read line 5 on page 196, or whatever. I have had zero problems with this method across about a dozen players.

It's never too late to explain your position and/or (re)do a session zero.

## You may have to talk to this player aside
If everyone has talked and agreed on a playstyle moving forward... and the player continues to be a problem, you should have a conversation with them. It's important to use neutral language and avoid things like "you're ruining my game". You'll want to stick to things like "I'm hoping this can be a collaborative story telling experience. There's no winning or losing, we're all just trying to have an enjoyable evening/morning/extra-temporal experience."

(Disclaimer: I'm not the best talker, so those might not be the right words.)

# Don't let one player ruin your hobby
I don't know if you're a good DM or a terrible DM. You might be awful, who knows? We were all bad DMs at one point or another.

The only two things you need to be able to be a great DM are:

 - Enjoying the hobby
 - A willingness to learn

That's it. If one likes being the Dungeon Master (you'll always be able to find players) and one doesn't think that they're too good to learn, then one can get better. Whether that means going from bad to mediocre, or from good to great, or anything in between.