I finished the main storyline of Control, and I absolutely would not have done so without activating the assist mode. I just don't get excited about fighting difficult fight after difficult fight. The game wore me down to the point where I just was not having fun any more, trying to live up to the challenge the designers had in mind. It's not rewarding enough to my brain. Too many instant-death pits, bullet sponge enemies, and enemies that respawn while you're still in the same damn room trying to find the thing you're supposed to destroy/interact with.
I loved the story, the aesthetics, the reality bending visuals, the strange lore, the creepy sense of dread.
What I didn't like: feeling super squishy all the time (even after getting the shield), the boring upgrade system that the game would have been better off without, the frequency of bottomless pits that are insta-death and send you back to the last save point, constantly having to play at my best to make any progress.
When I finally did activate Assist Mode (which is really good, with a lot of granularity to the options), and make it so that I wasn't made of tissue paper, and so that a full clip of ammo could reliably kill at least one enemy, I started to have a whole lot of fun with the game. I still died several times in some of the boss battles, since I didn't crank things all the way up, or enable invincibility, or one-hit kills, but I enjoyed things a lot more without my heart racing, and the pacing of some of the setpiece moments was a lot better when they weren't broken up by long loading times after each death.
I'll keep playing the DLC missions, which seem pretty fun (and have pits that don't instantly kill you, but reset you back onto the ground!)