I’d echo that trail trousers are a great addition. I bought some Altura eskers in last years sale. They don’t soak like tights, you can layer underneath and you never get wet. Finally, when they come off you hang them to dry and brush the mud off later – mine have never been washed and don’t honk.
re tight ankles – maybe I’m lucky but mine are fairly restricted over the top of some Scott Heaters but stay there. I get nothing flowing into the tops of my boots.
it’s made me much less avoiding for winter riding, which can only be a good thing.