htmx does not require many more round trips to the server, front end scripting is perfectly compatible with htmx:

https://hypermedia.systems/client-side-scripting/

in addition to native html features like <details>, etc.

htmx can often decrease the number of trips to a server because in the hypermedia model you are encouraged to deliver all the content for a UI in one fell swoop, rather than in a series of chatty JSON requests that may be made due to opaque reactive hooks.

I find Datastar to be a better replacement for HTMX, especially now that it can also do plain requests instead of Server-Sent Events. You also don't need Alpine.js combined with HTMX anymore.

First time I've heard of Datastar. Not sure what to make of it yet, but the video on data-star.dev is certainly one of the cutest things I've seen all year!

Many more round trips to the server is okay - it is the server after all and it is easy to scale it.

Does it matter how many round trips are made to the server if they're fast enough to be seamless?

I meant for the SPA-like experience.