Every build I test is designed for Ultimate Grimmest - if you’re asking what I think you’re asking, some builds are better designed to play a different build up through Ultimate (or until you have enough skill points) and then respec when obtain equipment / skills that your build is reliant on. Something like Riftstalker + D3 Skellies is something you need to wait until you have enough points to get the 100% Physical to Aether conversion before you try adding Riftstalker to the mix (or even just get it for the buffs / passives and then go for the other skills when you get the conversion). Once you get it, though, you’ll plow through even Grimmest content with ease.
The hybrid pet/player builds are more challenge builds than anything, but even then they can go up through at least Log on Ultimate Grimmest (and that includes Hidden Path - Mad Queen is a favorite of mine for build testing purposes). The squishier builds may have a more challenging time on AoM Nemeses, but I can only test so much that I’m likely only going to take my favorite builds out of the 20 or so that I post through AoM + Lokarr. The others are either challenge builds or prompts for Crate / mod devs to buff underwhelming equipment or classes.
I have write-ups for my 3 Riftstalker builds, but I’m going to hold off posting them until I finalize their equipment to make sure I maximize their efficiency and that I’m not relying on too much on OP equipment in the event things like Eurydice’s Wedding Bands get nerfed. Like I did for Storm, one will be standard pet build, one will be hybrid pet + player, and one will be full-player build.