You can change collision on multiple meshes at once, it’s just not in the place you would expect.
I found the answer on this thread: How do i set collision "use complex as simple" on multiple SM at once? - #6 by 7Jerry7 (thanks 7Jerry7!)
Basically you select your meshes, right click and select Asset Actions > Bulk Edit via Property Matrix.
The collision options you probably are looking for are under the Static Mesh tab, not the Collision one. Expand Static Mesh, then Body Setup, and you should find your collision options in there. Hope this helps!
