I probably wouldn't, since it is very use case specific what concerns are relevant. So more a suggestion to get an overview of the security requirements and privacy requirements one needs to deal with at some point and sketch some possible ways to make those requirements easy to solve when the time comes.

Examples of things to consider: zero trust, multi tenancy, permission structures, user data classification (for GDPR removal/extraction requests).

As a European, GDPR has far reaching consequences that may even dictate what other services you rely on. I.e. can you use that SaaS service for your product when it's located outside of the EU/EEC?