Add text chat for survivors
What if they added hotkeyed pre-existing text blurbs (because no one wants to be spammed or deal with toxicity) that survivors can use to communicate with one another (It's used in other DbD clones).
Example: "Killer is following me at <x>!", "Going for rescue, stay on gens!" "On generator at <x> location" "Heal me near <x> location!" "Hex Totem near <x> location!"
X being current survivor location and obviously they could make a lot more of these and have one of those text wheels for players who refuse to hotkey things. It could be a small text banner that stays over your portrait at the bottom right so it's not intrusive and can even be muted from the esc ingame menu where people check steam profiles if they wish.
AND THEN balance the game as necessary because it's literally impossible to prevent people from playing with their friends but at least give solo queues the option to play with their random teammates in similar ways. This serves to level the survivor players THEN you have justification to rework and buff the killers across the board as players "in theory" start to work together better even without 3rd party voice chat.
They could directly address killer perks at that point that are basically negated by swfs and make them more useful, aura perks for survivors are still useful as it gives exact information and honestly with a communication buff they could probably directly take some perk nerfs at that point.
"But my immersion!" - You're literally playing in the entity's sandbox while survivors try to thwart his madness over years and years of torture. They've developed mystic telepathy at this point since 1000s of hooks to their chest haven't killed them yet.