Before you reflexively downvote me here, just hear me out.
A second ring slot, with two simple caveats:
Secondary effects only, stat bonuses ignored.
You cannot equip two of the same ring.
For example, you could wear a ring of suffering in the second slot, but it would only act as a recoil if enabled. You could wear a ring of life in this slot. You could wear a ring of the gods (i), but it would only act like the holy wrench. You could wear a ring of wealth and get the gold pickup+RDT benefit. You could wear a brimstone ring, but it would only have the chance to bypass magic defence. You could wear a lightbearer in this slot, too.
I feel this suggestion would be good for the health of the game because it not only gives more opportunities to consider bringing along existing passive effects that are quite nice and don't see much love because of mutual exclusivity (RoL, RoW), it would also open the possibility for new rings to come into the game without adding to SwitchScape problems.
A downside to this is that, yes, it is a form of power creep, but I feel this is significantly offset by the freedom to have rings that do unique things that aren't dead on arrival because other powerful rings already exist and there's only one slot. In a way it kind of diminishes the amount of power creep caused by lightbearer, but also creates opportunity for more power creep to exist depending on how you look at it.
I really don't think it would be broken to have a second ring slot specifically for rings with passive effects.
As for how to unlock this new equipment slot, or whether or not it should be gated behind a piece of content at all is not something I have any good ideas about.