The modern web platform is capable and not bad at all to work with directly. I love seeing projects like HTMX and the recent hyperflask etc showing the way, but you don't need to buy into a project to follow this path, just use the web platform.
Edit: for a more practical example, you don't need to go down the web components rabbithole just for native reactive components, MutationObserver can watch for your template fragments entering and exiting the DOM and run your init/destruct routines on them. Now you can just push HTML back from the server with fetch or xmlhttprequest or whatever, and as soon as your component's HTML enters the DOM it will be "hydrated" by your init routine via MutationObserver. Honestly, add some event signaling and XHR and you're further along to a smooth SPA-like experience than you might think.
Web components, copy/paste CSS that does crazy stuff, all of these Web APIs [0]. However, Vue is my go-to. It's just reactivity with files that don't break "separation of concerns". Plus a community if I get stuck. However however, making something super slim bare bones is the most rewarding.
Edit: for a more practical example, you don't need to go down the web components rabbithole just for native reactive components, MutationObserver can watch for your template fragments entering and exiting the DOM and run your init/destruct routines on them. Now you can just push HTML back from the server with fetch or xmlhttprequest or whatever, and as soon as your component's HTML enters the DOM it will be "hydrated" by your init routine via MutationObserver. Honestly, add some event signaling and XHR and you're further along to a smooth SPA-like experience than you might think.