Start by pre-filling your own CAIQ v4 with an earnest “we don’t do this” or “we haven’t even thought about this” attempt: https://cloudsecurityalliance.org/artifacts/cloud-controls-m...
Then read through it and see what you can address immediately (EDR on your laptop, MFA on your cloud environments, etc), followed by role playing your client; “based on answers to this questionnaire, what would I not accept?”
There will be some items you can’t fix.
You’ll soon find out the majority of customers, including banks, governments, defence contractors, crypto startups — simply do not care. If they want to use your product, they’ll work with you.
It may be single-tenancy, it may require architectural changes, it may mean making it selfhosted with a time-bomb, but you’ll be able to address the requirements of the CISO, compliance monkey or executive.
I’ve yet to meet an industry or individual I can’t convince. Even if the product is a hot mess, half baked and radioactive — we’ll deploy it on a VM running inside of a VDI within the customer’s environment, because slopping together a migration path is _so easy_, and those early, highly regulated clients are worth it.