This will sound weird, but my player speed is so high that its rather tedious to get into the small transport rings. Would it be possible to create another variant that is two to three times as large?

Drive a tank to get in the rings.
I might add a large ultra-endgame version in some later update.

It would need rework of the network and connection logic, since different sized teleporters should not be able to connect to eachother or they would cause mayhem.

"drive a tank" lol, and he says it with chad profile picture

What about the option to just make them bigger using settings, not a possible quick midway solution?

Barrier logic cannot be simply scaled.
I don't think it's a good idea to publish a half-baked solution, but if you wish to customize the teleporter size you can do so by:

Remove triggering create_barrier() in control.lua,
Change texture scales in data.lua,
Change renderer position offset in on_built() in control.lua to account for scale changes,
Change areas under timed_teleport() in control.lua.

just toggle your exoskeleton off with Alt + E

First, I didn't know that is a thing. Second, RPG items mod still causes me to be fast, so my issue is still there