If I were you and in the United States, I would go hike the Appalachian Trail or something.
But these are much easier if they're already hobbies or interests.
Backpacking has been hit hard with covid though. As I understand it, hostels currently aren't quite what they were before the pandemic. And fear around this new variant will keep it that way for a while. Next summer things might pick up enough to explore Europe and beyond though, fingers crossed.
With the luxury of time, investing in oneself can be done in novel ways, e.g. flying or ocean sailing, triathlon, surfing, craftsmanship, golf.