It's good that you went with a larger tank. Larger tanks are less work, easier to cycle and clean, etc.
If your tank is near where 'the action is' in your home, your betta will be plenty amused by everything that is going on.
Oddly enough, most bettas enjoy interacting with people. They are sort of like water puppies (my betta wags her top fin whenever she sees me, like a dog would wag its tail).
They're brave, intelligent, and quite often their curiosity can get them into trouble! They will get their heads stuck in holes in your tank decorations (which can be fatal); they will jump out of the tank if left uncovered (also fatal); they will explore your tank vacuum a little too closely (possibly fatal, if you don't notice quick enough)! They will swim up your filter's outflow and get into the filter. They are busy enough on their own, and will keep you busy too!
What they really don't need is TANKMATES. Seriously! A really aggressive betta (male or female) will wipe out all smaller tank mates. Shrimp = food. Neons = food. Other bettas = death and destruction. Catfish = death and destruction. Guppies = death and destruction. Do you see a trend here?
I learned this all the hard way. You can do what you want. You've been warned, lol....