Ok Chromera Typing:
EExit makes you kind of a weird pivot. And for pivots one of the best things you can be is hazard resilient. Lando T is an excellent pivot bc of its typing. Similar for Mons Like Genesect/Scizor, Pheromosa for offensive pivots or Corviknight Tomohawk or Ferrothorn for defensive.
There are offensive pivots with less than ideal types that make up for it via speed or ability. Since ability falls flat for us speed would likely be the way to go.
Another place where EExit might shine is as a Hybrid Hazard Setter -> Late game Cleaner Mon (imagine something like Deo S that can set rocks turn one and clean with half health and a three attacks set late game).
For this having both very spammable STAB and a good Matchup into Hazard removal/other leads is really cool.
Imo two premier base types here would be either ghost or flying types. Both have really spammable mono STAB and solid matchups into Hazard removal and other Leads.
Flying having a built in Spikes immunity is great too.
These types would best be complemented by Ground or Fighting for better hazard resilience and complementary STAB.
There's a third potential that makes EExit interesting, which is high power nukes with offensive Stat drops/HP cut, which you can click and be immidietly switched out after
Fire types not weak to rocks, Grass Types, Psychic and Steel types as well as Rock types have access to such moves.
Of these I think Fire and Grass are best just bc -SpA moves are easier to handle than -HP.
Of all of these I like Grass and Fighting most, bc they have access to draining moves (or fire if you want bitter blade), which could enable you to potentially get back over the EExit barrier.
A last consideration is that a lot of leads are Ghost or Ground types (Pult, Kit, Lando, Ting Lu)
I don't think I have a clear favorite now, but some combination of Fighting or Grass with Flying, Ghost, Fire or Psychic would be cool, with some room for Dark types.
Combos that don't suck:
A+ Tier:
Psychic/Fighting: cool anti hazard removal matchup, stealthrock resist, great STAB Combo in CAP. Sucks into Ghosts
A: Fighting/Flying solid anti lead matchup, great STAB combo, great hazard resilience, pretty limited with moves though
A-: Fire/Fighting: Great offensive type, Solid anti lead, good variety of moves. Sucks into Pult and Lando, no hazard resilience.
Ice/Fighting or Ground: absurd Stab combo, solid anti Lead and anti removal matchups, no hazard resilience
Ghost/Grass great hazard removal matchup, solid anti lead matchup, solidly spammable Stab. No hazard resilience. Grass is weird
Ghost/Fighting: Great STAB combo, great anti lead matchup. Weird split between wanting Spa or Atk
Dark/Flying: great anti lead, solid anti hazard matchup, great Stab combo, spikes immune
B+ Ground/Flying: No draining, ok Hazard matchup, great hazard resilience, really spammable stabs
Fighting/Dark great lead matchup, stealthrock resists, solidly spammable stabs.
Fighting/Grass can take different directions with moves, has a solid anti lead matchup and stealth rock resist.
B: Grass/Psychic weirdest defensive profile. Pretty solid anti Hazard matchup, pretty good Offensive typing. No hazard resilience. Sucks into Ghosts.
Overall I'm looking for a typing, that can be really threatening Turn 1 meaning it's not too passive and can threaten a variety of mons, while being solid for a Pivot to come back later, either setting hazards/screens again or getting to cleaning/breaking with good STAB coverage.
Ideally if it's a Setter/Lead having a type that pairs well with spin blockers is cool.
We don't have a role here yet and boots likely is the best item. But looking at stat dropping moves, abusing Eject Pack plus EExit for a Hazard Setter/Taunt Lead seems really funny.
Also consider fairy Lock/Jaw Lock plus EExit