The problem I'm saying exists with JAM stack is that it's great for developers but bad for non-technical people -- wordpress is the opposite, and if I could get JAM stack properties out of Wordpress, I wouldn't use JAM stack for any projects which involved having non-technical people modify the site (which is a lot of them).
You could check out Strattic which gives users the best of both worlds - edit your site as usual in WordPress, and click a button to deploy a static, Jamstack version of the site. All the power of WordPress with none of the headache. https://www.strattic.com