Rule 0 still exists. This is meant to help give a quick distinction for playing in "untrusted groups" where you don't know what other people consider a "7." You can state clearly that by the brackets, your deck is considered a 3, but also mention that it plays out more powerfully, like a 4.
For most players, this is a pretty helpful guide:
- 1 is for your jank and meme decks. It's not designed to be strong, it's just to do something funny.
- 2 is for precon level decks. Not awful, but definitely not optimized. A number of budget decks and pet decks may fit in here.
- 3 is for your good decks, but with the caveat that they're not full of the salt-inducing "game changers" or Mass Land Destruction or 2-card combos that go off turn 2.
- 4 is for your best non-CEDH decks. Push it as far as you want, understanding that other people at the table likely did the same
- 5 is for CEDH. If you don't know what that is, you're not playing a 5, just a powerful 4.
I know that most of my decks are 2s, or a 3 with 1-2 Game Changers. None that would really be 4s, but sometimes I can play them at a 4-level table and still luck out into a win.
Online groups! There are great ways to play using things like Discord or other voice options, along with digital tabletops (roll20) or virtual tabletop applications (Foundry, Talespire, Tabletop Simulator or even the new beta for Project Sigil).
Online has its own set of bumps and friction points, but it can be a good way to get your feet wet with the rules and also practice the role play part. Just make sure that you're finding a group that is like-minded. There is often something called a "session 0" where the group will discuss the expectations in behavior and roleplay and responsibilities. It doesn't always happen with online groups, but in that case make sure you have a DM who is setting those expectations in advance.