I worry that it will never end or that we will have to continue things and make a choice on research we want to do. Like right now we will pass the chaos gods because of the triple down, traits and stats. But eventually we may have to make a choice. Not soon since the Eldar treatments are working but in the future.
Honestly, non-Lin world cleansing is not
that far off.
I mean, it will take at least a century with current research backlog, but...
-There is an option (unlisted, but certainly was there) to research chaos frequencies. It's incredibly dangerous due to corruption, but Ridcully doesn't have to worry about that anymore.
-From then, it could go similary to ork frequencies- find frequencies that destroy chaos (peace, calm, temperance, etc.). It would probably require research into specific chaos gods, but we could beeline towards chaos undivided.
-Then there's research into a thorough cleansing power, then greater version of it (to make it usable on planetary scale), then training people to actually use it.
While it would lack Lin's potency, you could spread this knowledge to other human polities, giving them a potent weapon against chaos.
I know it's a long shot, but with all the high-tier research Lin does, we have a headstart (e.g. nature of chaos gods => easier time finding their frequencies).