How can I rotate skeletal meshes?

I got 2 asset packs from the Epic marketplace, 1 has skeletal meshes oriented by X, the other by Y. They are the same type of objects and I would like to use them in the same way in my already existing animations etc.

Basically all I need is to take a batch of skeletal meshes and rotate them by 90 degrees.

Based on this answer, I assume it is not possible to edit the skeletal meshes directly in Unreal?

Since the assets are from the Epic marketplace, I don’t even have the FBXs. So currently the only way I can think of to solve this is Exporting into FBX, importing them into something like Blender, rotate it there, exporting them and reimporting into Unreal, while praying nothing breaks, all of this one by one - which sounds like pain.

Is there any smarter way of doing this?