If you buy into server rendering before you write a single line of code and understand it's a trade-off it turns out to be only mildly unpleasant in practice.

The best such codebase I can think of might still have been better off overall as an enriched MPA, but given how few normal pages it had compared to the app-ish bits - thereby making staying on a single technology stack a bigger advantage - I'm not quite willing to say it -definitely- would've been better as an enriched MPA. Not quite ;)