DKIM Authentication Fails at Gmail

Following migration from Google to Squarespace of my giorelli.net domain, occasionally the DKIM authentication does not pass when sending email to 10-30 Gmail addresses. My email provider is Gmail, as well. However, I'm not a Google Workspace customer; I simply use the Squarespace email forwarding to Gmail accounts.

Per other posts in the forum, my DNS settings seem ready to use email forwarding and include a DKIM record (refer to attachment). Nevertheless, the DKIM authentication fails when the Gmail server deems I am a ‘bulk email sender.’ The DKIM authentication successfully passes when sending email to a single or few Gmail addresses, instead. Any thoughts?

I searched the forum for the issue above and didn’t find solutions. My apologies if the issue has been addressed before.

Thank you