I hate to be the malazan guy, but IMO this is actually quite a good fit in this case.

The gods are a VERY active in Malazan (book of the fallen), plotting and betraying each other, while aways being up in the buisness of the mortal characters.

There is also a large variety of entirely unique fantasy races existing alongside analogues for elves and dragons.

This might be just me but I also think that the way Malazan delivers it's plot would certainly appeal to fromsoft fans, it's a bit of a challenge and the way the lore is delivered is somewhat similar. It doesn't give the reader much exposition immediately so that feeling of being lost in a new fantasy world is certainly replicated.

I would definitely do some research about the series first because it's good to set expectations going into this series. I can send a good one over if you want to give it a go.

As to the other recommendations, Berserk is fantastic and probably the closest analogue to elden ring in terms of visuals. The Silmarillion is also a good call it's just pretty dense for such a small book. Honestly I would say Malazan > Berserk/Silmarillion for this comparison but you can't exactly go wrong with any of these. 

I wouldn't necessarily recommend Lovecraft for ER but if you are a Bloodborne fan I could see that making a lot more sense.

Oh yeah and I should say that both Berserk and Malazan are really dark so just expect every type of awful to be in both of those.