Have you looked into what legal tech startups such as Ironclad offer in this regard? There are a number of contract-related tech products.
We are a legal tech startup building a SaaS that is primarily geared towards litigators at the moment, but we do want to expand our functionality to transactional attorneys in the future, and this sort of thing will very much be in our wheelhouse.
I would recommend SQLite + a nice usable interface tool like
datasette
https://github.com/simonw/datasette
Or SQLitebrowser https://sqlitebrowser.org/
(There are other generalized tools, search around to see if there are more suitable.)
You can store whole files, in addition to searchable text fields , and the single file is easier to share or turn into a more sophisticated “app” when the time is right.