Just started yesterday, and I'm a little lost. if anyone has some time to answer some questions I'd appreciate it!

1. Should I worry about gear? Or will questing be good enough?
2. What's a good realm to be on? I realized today I'm actually on a Japanese server.
3. Are jobs pretty rigid? i.e. white mage is always a healer, and paladin is always a tank?
4. Are mods really a thing for ffxiv? Tried a quick google search but they mostly seem for aesthetics.
5. I tried ff xi a long long time ago, and tried to play a taru taru warrior...and it was so hard to get an invite from anyone. Is that still the case or are all race/job combinations acceptable?
6. If I joined the gladiators guild, but then when I went to other guilds there are quests available, is it ok to take those quests too?

Any other tips are welcome, thanks for your time!