Doom and Elden Ring are games that have drastically different approaches to the idea of letting the player take on gods, demons, and various other unfathomable horrors. Unlike FromSoftware protagonists, Doom Guy is a character who can waltz into a room loaded with hulking enemies and run around dispatching them with reckless abandon. Meanwhile, Soulsborne protagonists can still be fairly easily bodied by a pack of low-end enemies well into the late game if the player isn't careful.
Which of these executions for similar concepts comes out on top is really up to the eye of the beholder. Many gamers within the community are perfectly happy with either, as both franchises sport rave reviews across a long history of successful titles, and they are quintessentially different from one another. What neither franchise has done yet is venture into the other's territory, though, which is perhaps where Doom and Id Software have an opportunity when approaching a future entry to the iconic hell-smashing series.
What If Doom Met Soulsborne Games
It's often been said that in Doom the real horror is the protagonist, and all the demons in hell are afraid of him. While not canonical, this is in stark contrast to the very core of every Soulsborne game made by FromSoftware, where already unsettling landscapes and creature designs are further enhanced by the constant tension created by just how quickly the player can find themselves hopelessly overpowered by any number of unexpected enemies. Doom has a creepy landscape along with demons that have only been made more grotesque with their modern visual upgrades, and what it's missing to make the series truly feel horrific is that tension brought about when the power dynamic shifts.
This isn't to say there's anything wrong with the way things work in Doom. It's a classic series that is attempting to pull off a much different tone than Elden Ring or Bloodborne, but a game within the series that holds similarities to those games could be an interesting way to further explore the wider world outside of just Doom Guy's POV. He's someone to fear in the series' hell, but someone else finding themselves in the realm of Cacodemons and Arachnotrons would have to find a vastly different approach to killing the enemies Doom Guy can take care of with a double-barreled shotgun or just his bare hands.
The Future of Doom is Open-Ended
The ending of Doom Eternal after both Ancient Gods DLCs left the door open for a world of potential when considering future sequels. The next game in the series has the option of following the Doom Guy story once again, and most fans would likely have no qualms following him right back down to hell for even more action. There is potentially an opportunity to explore other facets of this fascinating universe that kickstarted a lot of what lies at the foundation of gaming today.
It probably wouldn't work the other way around, however. Miyazaki has carefully crafted an image for the Soulsborne titles coming out of FromSoftware, and having someone like Doom Guy travel the Lands Between and can rip apart Fingercreepers like they're paper mache would clash pretty heavily with the overall tone of everything he's created. It's unlikely anything like that is coming in the Shadow of the Erdtree Elden Ring DLC or possibly future projects either. On the other hand, Sigil 2 is the only thing known to be in the works for the future of the Doom franchise at the moment. Id Software is a developer that almost exclusively focuses on FPS games, so the likelihood of the company jumping onto an action RPG seems like a stretch, but the idea would be interesting.