Few questions about PvP, ratings and sets.

[Mamut]

Ok so Im "only PvE" type of person. Im playing since late Vanilla and to this day I have like 5k honorable kills . And in arena last time I played I think it was in WotLK and it was few games with friend just for "fun".
Today I wanted to buy Elite armor from Legion for transmog for my lock (the black antorus pvp version looks insane) only to realise its not possible anymore due not reaching 2k rating in Legion. I was so dissapointed. And now Im thinking about trying to get that rating in BfA so I wont miss future elite sets.

Im well aware it can be hard and its very possible I will fail and wont reach that rating. But anyway I wanna try and now I have few questions.

1. Is the rating account wide or its unlock sets only for specific class? For example If I PvP as warlock will I unlock only cloth sets or also leather/mail/plate?
2. What I must do to get rating? In PvP Rated tab theres 2v2, 3v3, RBG. I need reach 2k in all of them or only in 1? If only in 1 which one would be easiest?
3. My current main is a Warlock (422 ilvl), I have few characters at 120 but Im not playing them. My old DH main sits at 390 ilvl, rogue 380 ilvl but I lost interest in him. Leveling also Shadow priest because I like casters now more than melee and wanted Zandalari troll warlock.

Which class would be easiest pvp wise for totally not experienced player like me?

4. How to get into rated PvP? Do people PuG rated arena, rbg or basically I have to find somehow a team and gets invite?

5. Any other tips and advices?

[Philomene]

You get some elite appearances starting 1400 but you get everything except the cloak at 1800, 2000 was since s14 up to BFA

You can get it no matter the bracket, be it 2s/3s/rbgs.

Once you unlock the tmog, you unlock it in your appearance tab so it’s usable by any character that can use it. Now since there’s no more class sets it depends on the armor type.

You can go play 3s as destro with another caster and druid or hpala, 1800 is pretty easy especially if you have pve items. You don’t have to do anything special, tank all damage and select a target that will eat all the incoming damage, if you have pve trinkets they’re usable and strong.

To get started I’d recommend looking in your friend list, get used to pvp, random bgs / skirmishes then when you get a good feeling you can start queuing. Avoid as you can lfg since a lot of players there are complaining they can’t find anyone but leave after a loss or just use their onetime 2k in 2s wotlk exp as argument of proof that you suck. Ofc there are some hidden gems in lfg but they’re fairly rare so use lfg if you’re ready to deal with toxicity of trash players.

Good luck