We've got some usefull resources for you.
cEDH (Competitive EDH) is Commander with a slightly different social contract where players expect everyone to try to win and play optimal while doing so (and have fun trying to win).
The cEDH meta is known for fast and efficient combo’s, highly interactive gameplay where players will try to win or interact from the very first turn. There are no hard feelings for nasty strategies, as long as the goal of a strategy is to win.
While there is still a lot of politics involved in the game, situations of king making, and spite plays are generally not appreciated.
There is a vey nice curated database that give a good overview of cEDH commanders and strategies. This is not a tier list, but a great resource for deck builders and players more new to the meta.
Below you’ll also find some nice youtube channels with gameplay that will give a good impression of what to expect in games.