Yep, that's a lot of vertex transforms. The plus 248 bones, 78 constraints, 139 visible attachments -- all that makes a pretty heavy skeleton. That may be OK, after doing basic optimizations, depending what else you are doing at the same time and the devices you are targetting.
The first thing to do is use prune. Also see this section (both whole pages really):
https://esotericsoftware.com/spine-metrics#CPU-usage
That will reduce your vertex transforms. You can look at reducing the number of bones. If you have extremely detailed sections of the skeleton that don't actually need, redo them to use fewer vertices/bones/etc.
13 clipping polygons is very likely to be unnecessary. Clipping is very CPU expensive. You want to use as few clipping vertices as possible, which is 3. The size does not matter, making it huge is fine, but use 3 vertices. Next you want to clip as few vertices as possible. That means clip as few attachments as possible and those attachments should have as few vertices as possible. Simplify the clipped parts of your skeleton.
Even better: remove the clipping attachments except for what you absolute must have. You can duplicate meshes and cut them differently, then swap between them to simulate clipping. Otherwise you can hide images behind others instead of using clipping.
Lastly, your metrics don't show it, but it's a common mistake so I'll mention it: avoid deform keys in most cases (see the linked docs). Use mesh weights instead, where you key a bone that affects the mesh instead of keying the deform for the mesh.