Hi,
While RouterOS does allow for multiple key sizes (1024, 1536, 2048, 4096, and 8192), notably missing is 3072 as a common compromise between 2048 and 4096.
It would be nice if either free choice of key size was possible or at least to add missing NIST recommended key sizes: 3072, 7680, and 15360.
Example of failing command:
/certificate add name=client-template common-name=client.example.com days-valid=3650 key-size=3072 key-usage=tls-client
Tested on RouterOS 6.38.1