How do you make PE more bearable?

Can't say that you'll find much variation in expectations around work quality - PE firms recruit out of banking analyst programs for a reason - but differences in the cultures across firms means that some work environments can be much more pleasant than others. If you really like the day-to-day of investing, try to carve out some time to explore other firms (though lateral market is tough right now) to see if you can find a better fit. It's not impossible to find places that have a genuine culture of mentorship/apprenticeship (though much easier to find in banking, since they hire out of undergrad), and, given your experience, your ability to discern whether the folks you're interviewing with prioritize "soft skills"/people management should be more refined.

That being said: 1) if you'd like to pursue a lateral, think about a credible/passable narrative for why you want to make that jump (plenty of material on this site); 2) if you want to pivot and do something very different, initiate the recruiting process now by reaching out to your network, mapping out ideal roles, etc., since the process could very easily take more time than you anticipate in this environment (and you don't want to reach the point where quitting seems like the best/only option).

In the meantime, to make your current seat more tolerable:

1) No shortcuts to this, but you need to develop a system that ensures you produce flawless work, which could include infinite checks in your model, taking the time to create/format outputs in excel that would otherwise be labor-intensive and data-centric powerpoint tables, and good old-fashioned checklists/logs that help you sense-check your outputs and keep track of which figures should tie across your different work products... I'm not saying this to patronize you, it will just take an enormous amount of pressure off of yourself if you have confidence in your process (even if something ends up being incorrect, it'll at least take some of the mental strain off of you when you send work upwards/present it)

2) Slow-play everything. Over time, you should be able to recognize patterns in the working style of the folks you work with/for (and the folks above them, etc.). Understand who triggers the stressors you're describing, and when that's likely to occur, and be intentional about where your time is best spent given the context. Position yourself such that you're more likely to work with individuals you prefer (at minimum, there are degrees of bad; your team can't be uniformly miserable). If you're worried about references for future investing roles, try to have some perspective: a) you only need to provide 2-3 references total in most processes, which can be from different roles, so don't worry about needing to please everyone (though backchannel references may not be uniformly positive if you happen to end up on someone's bad side in particular), and b) if you think you rub someone the wrong way, in 99% of cases that person will likely completely forget whatever incident stands out disproportionately in your mind (focus on having positive interactions in other contexts, i.e. happy hours)

3) Unless you're at a shop with a particularly stressful culture, little things that take a disproportionate amount of time (relative to the subsequent payoff) likely do not matter as much as you think. Think uniform formatting, grammar-related typos (misspellings stand out more), etc. I've been at two MFs, and while both experiences were high-velocity and oftentimes stressful, I figured out what really mattered; this can vary by individuals within the same firm, but generally speaking there were things I could get away with/cut corners on that would allow me to shave off an incremental 30m-1h depending on the deliverable. This adds up over the course of a process (or any given day, really) much more than you would think, and allows you to devote time elsewhere in your work (see point #1, above) or otherwise gets you home at a more reasonable hour