Remember that other Eric? Eric Robert Rudolph, perpetrator of the Atlanta Olympics bombing, among other crimes?
He disappeared into North Carolina's Nantahala National Forest for some five and half years. The feds mounted massive man hunts, and the FBI offered a $1m reward. He was finally caught by a rookie cop while raiding a dumpster behind a grocery store.
There was a guy outside of Seattle that had spent years building an underground bunker in a wild state park about 45 minutes east.
He murdered his wife iirc and then fled to his two-room hidden bunker.
Except everyone knew that 2-3 days a week he would go up there to go “hiking”. Found his car at the parking lot of the park. Meanwhile they were searching his records and found he had purchased lots of home-improvement things over the years without using them at home (tar paper, metal duct work, pvc pipes, etc.)
I think they found his bunker in just a few days. He ended up dead.
An underground bunker like that might be okay in a SHTF situation when there is not a large, organized search for you. But if so, I think a mobile and evading technique would be the way to go.