Yup, it's so hard to make resource expending non-combat encounters without effectively sidelining some of the party members. If you build an encounter that effectively requires spell slot expenditure, the martials are basically relegated to an audience position. And if you build an encounter where spell slot use isn't absolutely necessary, the party will try every imaginable way of conquering it without using up resources first, defeating the whole point of forcing resource expenditure.

I guess one key part of this issue is that generally speaking, caster resources (slots) have universal uses in combat, exploration and social interactions, whereas martial resources only ever have combat applications. This, in presence of resource expending non-combat encounters, kind of creates a situation where your choice of caster or martial decides whether you want to participate in the game the entire time or just half of it.