Mihail, you've been doing this since 2015. Is it possible that you still have some things to learn? Right now you're equating mature/stable == old/bad. You've come up at a time when it's been super trendy to push everything to the client, and I promise you that this works in a pendulum cycle. Meanwhile, if you keep drinking your own KoolAid, you'll convince yourself that you just happened to luck out and learn the methodology that you're going to fight to prove is the best. It's not a good look, and long term, it's not the hill you want to die on.
Also, this notion that everything has to be done with microservices and all-static front-end everything is just the regurgitation of propaganda. The massive pushback against this march towards the edge is already well underway. I've been building and scaling teams since the late 90s. You don't have to agree with me, but you don't get to squirt testosterone all over the carpet and bleat about how my views are "pure inertia". You're being a dick.
Straight-up, the first and best thing that comes to mind that is easier to do with server rendered UI is state management. You can suggest that Turbolinks is a "last resort hack" all you want, but frankly it's just not a credible statement. Using Turbolinks and a library like StimulusReflex, I can build reactive user experiences that load faster and smaller, render and update faster, and I drastically reduce the complexity of the logic by not keeping any state on the client at all. It's a breeze to develop, it's easy to employ Russian doll caching, it's actually a lot of fun, and gosh, it's good enough for 6 of the top 10 YC companies of all time.
Honestly, everything I do with Rails, TurboLinks, StimulusReflex and Stimulus, I can build it faster than a team of JS devs. I'm not sure that I believe you've ever actually tried these tools, or you wouldn't be saying what you're saying.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.