The best 1st party dev is Mike Johnson (he did the S.55 and the Albatross), because he keeps improving his planes rather than the standard "ask Microsoft" answer.
You can see how he's active on the Albatross thread on the MSFS forum too.
You really need to read the product descriptions. The mod in the marketplace is useless for 99% of users, it simply enables independent FMS.
Everything is otherwise in the base sim already.