There's a trillion possibilities for 8 characters of bech 32. How many CPU cycles are be needed to check one? I'm assuming there's not a better method than brute force, right? 

 Depends on the CPU. One of my machines can do a quarter million guesses per second so it could easily take a couple months. Just hoping I get lucky. 

 250kHz! That is way slower than I was expecting... couple months is right. It'd be $25-50 in electricity too. 

 i wrote one of these: https://github.com/mleku/vainstr

there isn't currently any acceleration or AVX implementation to speed up deriving public keys so yes it's one of the most compute intensive operations you can do on a CPU short of long division

i wouldn't know exactly how many instructions are required, probably some poking around with a disassembler could reveal this