Backup to B2 with a write-only permission key (no delete)

Can I backup to B2 using a key with only read- and write-permission, and the use another key with additional delete permission when doing retention running from another server to protect against backups gets deleted from the data-server.

How stable is the B2 API on Kopia? Restic does now recommend using the S3 API as their B2 library seem to have issues in regards to error-codes making it difficult to track errors.