Can't find this and it seems really dopey to create a feature for non-destructive editing that itself can't be changed non-destructively.

No, you can't do that. And personally, I don't think it would add any benefits. By the time, you would open the properties of a filter layer and change the type, you can just make another layer with another filter and delete or just disable the previous one if you are kinda sure which filter to go for the desired look. If you want to play around though, then yeah, filter layer won't allow that as of now.