Use deploy keys instead of access tokens for pushing to Git?

[davereid]

We'd like to not require user access tokens and instead make use of a write-access deploy key to the other repository for the split.

[richardhj]

You would need a deploy key for each sub repo, quite an effort.

Have you tried the new granular Personal access tokens? You can define - as the name suppose - granular access tokens with write access to specific repos.
(only downer is that they must be manually renewed once a year).