So I was reading over the Simic Hybrid's possible adaptations and noticed Manta Glide:
You have ray-like fins that you can use as wings to slow your fall or allow you to glide. When you fall and aren't incapacitated, you can subtract up to 100 feet from the fall when calculating falling damage, and you can move up to 2 feet horizontally for every 1 foot you descend.
So I used to cast Dimension Door 500 ft. above myself and then travel 1000 ft. in a turn. But my DM is a "RAW strict bitch" (her words not mine) and accepted this answer.
So trying to break the game the other way I now Dimension door straight up and then glide down slowly over the next 33 turns (since DM won't let em take more than 30 ft. of movement, I only have to descend 15 ft.).
Comparing this to 4th level fly it has half the speed, half the duration, half the targets, and half the up/down control, but it doesn't cost my concentration.
My idea however is that if I take 3 levels of Echo Knight (DM now allows the critical role classes due to Vox Machina) I'd basically be getting unlimited Misty Step spells so long as my Echo stays alive.
You can use a bonus action to magically manifest an echo of yourself in an unoccupied space you can see within 15 feet of you. This echo is a magical, translucent, gray image of you that lasts until it is destroyed, until you dismiss it as a bonus action, until you manifest another echo, or until you’re incapacitated... If your echo is ever more than 30 feet from you at the end of your turn, it is destroyed.
As a bonus action, you can teleport, magically swapping places with your echo at a cost of 15 feet of your movement, regardless of the distance between the two of you.
Since my Echo can go upward 30 ft. a turn while I can limit my decent to 15 ft. per turn while gliding, does this mean I can stay aloft forever by turning in circles so my echo can catch up after we switch places?
Edit: My DM has had a change of heart seeing my new way of breaking the game (and having had more than one session to think about it, in her defense). She now interprets the fins to be more like wing suiter style fins. So I gain falling/gliding speed more appropriate for a wing suiter which half she has ruled at half that given in XGtE. So I "descend 250 ft. first turn, and each subsequent turn". Thank you so much to all who read my post and helped with an answer.