This is where it helps to have a diversified cap table. In our case, we have a set of angels -- each with their own expertise.

All of them lead busy lives, but we can get many hours of feedback by picking a subset to talk to on a particular subject. E.g. we have a "former CTO of large SaaS company"-angel who we specifically call with regards to tech stack; an "ex Head of Product" we ask for feedback on product etc.

As an added advantage, it almost automatically leads to strong mentor-mentee relationships on a personal level.