In 2023, you can get 8k back on heat pump install (and some more if additional electrical work is required, which is likely the case), if you make under some income threshold, thanks to the IRA bill.

In general, heat pump in mild climate should cut your heating bill by perhaps 50%. And it can do AC, too!

I'd also check out your attic. Most of WA is supposed to have R49 in the attic, my 1970s home had R .. 10? 20 in spots? Naked elsewhere? Adding R50-60 in blown in insulation was a multiple-weekend DIY job but totally doable. Makes the house incredibly much nicer to be in, even in mild September days.