I would like to submit two feature requests for Hosted DKIM that I believe would enhance its functionality and improve its performance in specific scenarios.

DNS Flattering for Hosted DKIM

Unlike SPF, which has a longer timeout value of 20 seconds, DKIM lacks a defined timeout in its specifications.
As a result, DKIM is subject to the resolver’s timeout, which can lead to PermError or TempError due to even minor delays in the authoritative DNS or resolver.
To address this issue, I propose implementing a DNS Flattering feature for Hosted DKIM.
This would enable Hosted DKIM to respond faster, particularly for DKIM records provided in CNAME format by services like Amazon SES, Microsoft 365, and SendGrid.

TTL Configuration for Hosted DKIM

Currently, users cannot set the TTL for Hosted DKIM.
I request the addition of a feature that allows users to configure TTL values per selector.
By setting a longer TTL, I believe this could help reduce DKIM-related TempError and PermError issues, especially with resolvers like Microsoft 365.