Soft proofing Raw or JPEG?

I’m looking at Soft-proofing tutorials on YouTube and understand the basic functions, etc, but I’m wondering if soft-proofing should be done in the Raw file or the JPEG. Or does it not matter?

Also, should sharpening be done after the edit adjustments?

Really interested to hear about other people’s workflow.

For clarity, I’m sending to print at a commercial lab using their ICC profile.

Ta muchly!