If you are looking for that feeling of dire dread and the feeling of the impossibility of saving the caving world while doing your best against all (committee) odds then check this out.
Great when it's too hot or raining or someone says CSCC, CNCC, CCC, BCA or CRoW, etc. followed by a strange ritual dance ...
https://www.chaosium.com/call-of-cthulhu-starter-set/
Great fun and there are a few solo adventures available too.
The starter rules and a couple of adventures are free download from the website. The box set is really good as are the adventures.  More investigative than the D&D traditional dungeon siege approach. Basically you have to save the world without being dead or insane.
Maybe there is a reason the Hunter's is locked in time and Eldon Hole won't give up its secrets.
Fortunately I've been investigating said things and I can say I'm still completely sane...