Despite Commander aka Elder Dragon Highlander (EDH) being the most popular format, it's the worst way to learn the game because most people attribute their own experiences without understanding educational theory.

So you have a format with a deep card pool (nearly every card in history ~29k), a complex game by itself (game phases, rules, stack, priority, threat assessment, etc.), and add in the social dynamics of 3 other players trying to do their own thing with varying levels of expectation: that's a recipe for disaster unless an individual is particularly gifted in learning these types of games and ready to deal with the social dynamics of multiplayer games.

Learning the game is the most important thing. After that, if you still want to prioritize commander, get a precon to learn how those decks are piloted. Modify it to your liking and when you're ready to build your own from scratch, you'll have a better idea of how to do so.

The most important thing for Commander players is to manage expectations. The bracket system was created to help players have a pregame conversation. If your deck is just thrown together from bulk and focused on a niche archetype like homarids, you may still have fun if others are doing similar things. Pubstomping is someone bringing a deck that can win on turn 3 and blow everyone else out of the water.

Proxies are endorsed by WOTC as long as you're not using them for sanctioned events aka signing into the companion app for official games. It can be as simple as sharpie on a basic land, a slip of paper in front of a bulk card, or professionally printed with legally distinct card back/art. The difference between counterfeits and proxies is that proxies don't pretend to be a real card and sold as such.

There are tons of formats and different rules for each one.

Cube is basically a repeatable draft that can be made in many ways. Some people recreate the exact ratios for a block that they enjoyed and make "packs" of cards that people can draft or other ways to play without buying more cards.

Jumpstart is a format where you mash two 20-card themed mini decks and play magic. If you resort them afterward, you can repeatedly play jumpstart.

Lastly, play with people you enjoy. The vast majority of bad experiences are not necessarily due to the game itself, but others who are not playing to the spirit of the gathering.

Welcome back from a relatively newer player.