I recently made the switch from a Gatsby-powered version of my blog to a traditional server-templating based one. Currently there's zero JS on my website. The immediate impact is that my website is much more lightweight and loads and renders much faster. I plan to A/B test the visitor behavior across these two versions and share the results.
Though if you really go all in on no-JS (which I understand what OP isn't recommending), there are certain issues. Like if you have a "subscribe" button at the bottom of your page, using a non-AJAX POST request to submit the email will not get you to the bottom of the page by itself (which would come for free if using JS). So using JS can provide a better UX in these aspects.
I really wish HTML5 supported the image loading style where a very low-res image is encoded in base64 with a heavy blur, and then the real image is loaded later and then replaced. That's the default in Gatsby (and its clones), and it truly does feel quite nice. You have a huge (0.25MB, 1080p, never cached due to bad ETAG generation) JPEG that takes at minimum 1.6 seconds to download, and keeps showing the browser loading animation while it's active, while the image is loaded in vertical chunks at a time. Firefox puts a turtle next to that asset to show that it takes a while to download.
> much more lightweight and loads and renders much faster
Were you hosting it on the same host you're currently using? The downside with server-side templating is that you can't use a cheap global CDN like GitHub Pages or Netlify, which will be faster than your own servers in pretty much every case. The few extra KBs of JS (compressed) is likely offset by the latency of physical distance.
Though if you really go all in on no-JS (which I understand what OP isn't recommending), there are certain issues. Like if you have a "subscribe" button at the bottom of your page, using a non-AJAX POST request to submit the email will not get you to the bottom of the page by itself (which would come for free if using JS). So using JS can provide a better UX in these aspects.
EDIT: The blog in question: https://pythonautomationtutorial.com