I want to buy a winter coat that'll be my go-to for years or even decades. Given the following guidelines, what would you suggest?

-No more than $400
-Slim-fit
-Charcoal preferred, navy considered, maaaaybe black if I was otherwise BANANAS over it
-No hood
-Prefer a substantial collar good for turning up in bad weather
-Not double-breasted, unless it’s a pea coat
-Prefer more traditional styles like pea coat or overcoat, don’t want anything super-formal

Thanks so much for any guidance!