Imho, trub is a major downside of all in one/BIAB brewing. Ideally, you would want all of that "stuff" that was boiled to have been left behind in the mash. I know the prevailing arguments are it doesn't matter, but I believe it does. That is why I lauter from the mash recirc to a separate pot, clean out the Foundry and pump the clear wort back in for the boil. All one needs is an $18 pump from amazon and any type of pot with a spigot.
With regards to the spigot, I have struggled with clear wort to the fermenter as well. The Foundry is a pretty small diameter boil kettle, so there is not a lot of room for sediment & hops to go away. So I use a hop basket throughout the boil then run the chilled wort into a settling bucket. Let it sit covered while I clean up, then gravity transfer super clear wort to my fermenter. Once again, I am aware of the conventional wisdom that trub doesn't matter etc..., but that is how I do it.