Doom playthrough is mostly about picking your battles and being prepared. Early game you can do the graveyard cleanup with the Indiana Jones lookalike, or what I prefer is to do the Crystal Mine cleanup mission on your own - if you take your time and don't rush, you can do that one with just a shortsword and no stat investment guaranteed (plus the Deep One artillery quest is nearby, which is another good chunk of XP early on). Stealth is a must, and usually the hunter outfit from Fishtopia is my go-to because of the passive SCU and speed buff (SCU affects your detectability even when you're not sneaking, and speed lets you gain distance without spending stamina on sprinting).
Once you're established, it's a matter of having enough blue potions quickslotted and playing carefully. Funnily enough Noer is the most dangerous for Doom runs imo, as 90% of my games ended because I got rushed down by bandits in the tight streets and alleways. For the big quests, there are some that not worth doing (like stealing the Muskets), but playing through Cecyl's questline and even rescuing Cocona is feasible as long as you prepare well enough and know what's going to happen and what to expect in advance.
