Contentful has a free plan, and a quite robust typescript node.js module. If that isn't what you're looking for, there is also plain REST api. It wouldn't hurt to try it out.
I found that in working with both Prismic (a contentful competitor) and contentful, contentful still came out on top because of their strong node.js module, as well as their import/export, environments and api key management, etc are miles ahead.
With prismic, the pricing is very nice value but that value quickly dissipates once you spend all your development time trying to tackle bugs, locale issues and redundant data entry because you messed up an instance and want to recreate it. Use this experience when considering CMSes, it's not just all about features and pricing, but developer experience.
The only downside I see are paid plan pricing (next tier is 500 a month if the free plan doesnt work for you).