I’m looking at your armoury, trying to suggest a plan, and not quite getting the picture. Have you been taking breaks, or logging in only a couple times a week, maybe?
You have opened Nazjatar, and are working through it without flying, which I know is quite painful. Also Mechagon.
Do you do your Emissaries regularly to get rep for flying? Your Emissaries should also be giving you ilevel 400 gear now, and will start giving 415 gear soon. Also, you should have picked up better rings and off-hand just from regular world quests by now. Right now I’m seeing a Calligraphy (ewwwwww! 
) World Quest in Drustvar that should offer you a ring upgrade.
Do you use addons? I’m thinking the addon World Quest List should show you WQs with upgrades, and the addon Pawn will show you at least approximate upgrades. Correct use of Pawn requires you to sim yourself, but one step at a time.
Anyway, you are in gear range to start doing Mythic-0 dungeons now, though since most people will be ahead of you in gear, it may not be easy to get groups. I see you have done only a couple of dungeons on Heroic. Mythic-Plus is all about knowing the dungeons, so doing a bit of practice in Normals or Heroics just to learn the layout can be a first step.
You should join the Community Scared of Dungeons. They are a great and friendly bunch of people who will at least point you in the right direction. That might also mitigate your guild problem.
In the game, if you copy the code
BoLReWSqWo
into your Join Community request, (use Guild and Communities button → Join Community) I think that will auto-join you. Then say hello, and ask any questions when you have them! They’re really very nice.
Have you ever used the Manual Group Finder to do any form of Mythic dungeon? Groups will be found under Premade Groups → Dungeons. You will see a long list, mostly of numbers, those being the M+ levels people are going form and the name of the dungeon when you click into it. You would want something advertised as 0, or +0, or “normal” for a Mythic-0 to start.
I’m conscious that what I’m saying may not be on target for you. Maybe we could help more if you explain what you do in game now, and what exactly you would like to achieve?
If I were you, my immediate action plan would be:
- Do every Emissary the Gods send for rep towards flying
- Target any World Quest that offers an upgrade for those rings and that off-hand.
- Keep making (slow) progress in Mechagon for rep, and towards opening up access to their rings and trinkets.
- Spam Heroic Dungeons to learn the layouts for later use in Mythics.