Try scrubbing the walls with TSP (or most likely ‘TSP substitute’), you can find it at any paint or home improvement store. Then coat it with a good primer like KILZ to seal it all in. You can throw whatever cheap paint on top of the primer (grab a mistint from the paint store).
Save your receipts and anyone but a horrible landlord should let you deduct that from your rent.
I’m also living in the attic of a 120 year old house learning to fix stuff via youtube and This Old House reruns.
Nothing stopping you from installing a “whole house” surge protector on that particular circuit. They aren’t that large or expensive.