Lawyers will copy-paste something standard. We should probably come up with something basic first. The HubSpot terms seem like a good start, since we should consider the California CCPA as well.
This is something the CT needs to do since Spark is their thing and they bear the legal risk on this. Should probably stop EU signups until this is in place. It's irresponsible to allow EU signups for a non-compliant service. The legal risks to the organisations using Spark and to the LLC are pretty severe and all GDPR liabilities are shared by all parties in breach.
We probably have a few issues for GDPR on the website. I found this one: marketing/marketing-admin#2 (closed) (which you linked to this issue, but for some reason is not showing up).
Starting from the HubSpot terms may get you close (worth noting that the terms themselves are intellectual property and copying them verbatim is not a great idea!)
We can buy a template, but it's a fairly short and easy to understand doc, and other ToS can give us a good idea of what might apply to our specific situation.