11-36 Rear cassette for hilly area?

The relatively inexpensive workaround is a wolftooth road link. This will increase the size of the cassette your derailleur can handle but not the wrap so you have to have enough chain to handle the 36 with your big chainring but it won’t suck up enough chain if you go small/smallish. It works fine on the cheap.
Other solutions cost a lot more, though they might work better in the long run.