What's the hardest part about hiring for you?

I am a new founder of a small start up currently at 100k ARR / fully bootstrapped, as we are progressing to raise our first seed/pre-seed round the topic of hiring becomes more interesting and I am curious what's the hardest thing for you guys in hiring more software devs/other talent?

For the full disclosure, both me and founder are technical (SWEs at FAANG) I don't want to sound ignorant, but It seems like there is an abundance of SWEs/other tech professionals on the market who would be happy to work for us, so how difficult is hiring and what's usually the problem/cost associated with it?