That's the powerhouse of the verse though.
Just an example, itzal is a thing. There are TONS of ways to become invisible in warframe. Enhanced senses doesn't work on an invisible dude unless shown and stealth, please, against warframes.
Yes you do. No you can't throw things, you can enter yourself but outside of warframe abilities nothing thrown outside the rift works. Bullets, attacks etc. He can think that, shame it won't work cus the guy outside the bubble is in a dimension of his own.
That's stated where?
Dude how many do you want me to name? Nyx, baruuk, equinox, any warframe who can 1 shot, the operator mind haxing, Nekros, Ivara, Harrow, Frost, etc. They all 1 shot. And don't you even try to say they can't get a move on Gremmy, considering all the stealth, invisibility, silence, teleport etc.