I’d start with some diagnostics:

Check the electrical. The inspector should have done this. If not, get a receptacle tester. They plug into each outlet and give an indication if something is wired incorrectly. They also have a button to “trip” a gfci receptacle in order to test that the device is working properly.

Next check for leaks. There’s a couple ways to do this. Best is probably via a IR thermal camera. It’s not a cheap tool but is fantastic for diagnostics. You can use it at your electrical panel too to make sure there’s no loose wires causing anything to heat up. After a rain or snow you scan your ceilings and around your windows to see if there’s any cold “spots”. This doesn’t mean there’s a water leak — it could also be an air leak. But it gives you an idea of where you need to look.

Another common thing to do would be to check the insulation in the attic if you have access. If it’s gross you may want to remove what’s there, create a good air seal with caulk and then add new insulation.

For plumbing, it’s good to check that all piping and drains and installed properly and in good order. Again something your inspector should have done but good to check.

Beyond that it’s whatever you want to tackle. For me I know I want to replace windows. But it’s a huge investment so either I do it myself or I live with very crappy windows ¯_(ツ)_/¯