It's not exactly what you asked for, but the public transit and multimodal focused apps are generally much better at this stuff. I like CityMapper and Transit.

Neither is good for turn-by-turn directions, but both are good for "what are all the different ways to get there"

I wish I could add certain streets and routes to some sort of block list.

There are certain roads I would be willing to spend an extra 10-30 minutes driving to avoid. (And certainly would not get on them on a bike!)

Not to mention “public transit but with a waypoint” which is too advanced for all mobile apps