Fleemo wrote:

If you've placed a thick layer of bark mulch over your flower beds,
how do you go about amending the soil with compost come Springtime?
Do you scrape aside the mulch, work the soil, then return the mulch?
Or do you work the mulch into the soil itself, then apply a fresh
layer?

Topdress. Don't bother turning or scraping. It's work, and it
disturbs established soil structure.

As others suggest, topdressings should be chosen to attract earthworms.