Optimal Choices for Gritty Realism

So I'm going to be in a game with Gritty Realism resting (8 hours = short rest, 1 week = long rest), and spell points for non-warlock casters, and am wondering what are the best choices?

Ideally I'd be looking for abilities that are either always-on or that refresh on a given time-scale (at midnight, at daybreak, once per day, etc.).

The Warlock looks really tasty for it's invocations that allow you to cast certain spells for free.

If I was going to play a game under those conditions, I would play either a champion fighter or a cleric with the life domain, since they can recover HP on a short rest.

Tome Warlock (lots of at-will magic, at-will rituals, and some slots for special occasions), or rogue (lot's of at-will skills and mobility).
Fighter would probably be third.

Well,

It also kind of depends on the extent to which the number of expected encounters over time also scales back. As the number of encounters per short/long rest increases, always-on and at-will abilities become better.

Champions become better relative to other Fighters. Smite becomes kind of meh. Rituals and especially cantrips matter more. Not needing to sleep while resting becomes rather more valuable. Regular spells are nerfed hard. Moon Druid 20 becomes even more awesome, especially to every other Druid who takes it hard, and Wizard 18 also improves. The "I know many cantrips and am proficient in many skills" build becomes less of a novelty and more of an approach. Gnomes with at-will casting of non-detection become the best Abjurers. Warlocks are a mixed-bag: Their invocations become relatively better but their spellcasting gets hit hardest of all, since they don't get spell points. Swashbuckler rogues become the best at charm. Capstones of the 1/long rest variety are worse; capstones that replenish a completely-used power at the beginning of combat become better.

Anyway,

Ken

Warlocks that get 2 spell slots per day plus at will invocations seem awesome... especially since you only really need 3 levels of warlock.

Magic initiate for cantrips also seems good.

Rogues are loaded with at will abilities.

Bards and battle masters have a lot of short rest abilities.

Also, when I played in a gritty realism campaign we made an average of one roll per game day, which made the Lucky feat very good even though it took a week to refresh.

Racial Spells!
I knew the was 1/day spells, but I wasn't looking at races.