unfortunately, we do not support other forms. Just the default comment form is protected by ASB at the moment.
Are you using the official plugin for sendinblue?
https://de.projectdmc.org/plugins/mailin/
It looks like they are not having a honeypot feature and rely on Double-Opt-in and reCAPTCHA only:
https://projectdmc.org/support/topic/honeypot-to-prevent-spamming/#post-16046889
If you search for “spam” in the support forum for this plugin you can find the same answer on many threads.