We have a scenario where we work with programmatic partners to get demand via RTB for matched users.

The client will request each partner's trusted server using the Protected Audiences API. We can end up with many of these requests for one impression.

We are currently doing this activity in the backend before we return the ads/creatives to the client.

Going forward, we will move the bidding activity for this flow to the client increasing the chances of causing page performance issues due to many network calls. As you probably know, making these network calls and running logic in the client can block the main thread and cause JS execution challenges that can impact SEO (Core Web Vitals - FID/INP) and harm the UX.

Have you considered these aspects when migrating RTB-matched user flow in reaching out to trusted servers from the client?