The summary.
META-FRAMEWORKS REMOVE DECISIONS EVERY APPLICATION OTHERWISE MAKES INDIVIDUALLY
Routing, rendering strategy, data loading and build configuration.
CHECK WHAT YOUR HOSTING SUPPORTS BEFORE CHOOSING ONE
Some require a runtime shared hosting does not provide. A static export is servable anywhere.
ESTABLISH WHICH CODE RUNS WHERE
Server components ship no JavaScript for themselves, which is the largest available saving — but using browser-only features in them fails, and secrets in code that also runs in the browser are exposed.
CHOOSE THE RENDERING STRATEGY BY THE CONTENT
Static where it rarely changes, server rendering for personalised content, and never client fetching for content that should be in the initial response.
Check what the initial response actually contains by viewing the page source, not the inspected document.
TEST BY NAVIGATING DIRECTLY TO A DEEP ROUTE
Static hosting needs configuration for client-routed paths, and the symptom is the homepage working while every other address returns not found.
TAKE THE PROGRESSIVE ENHANCEMENT PRINCIPLE REGARDLESS OF FRAMEWORK
Forms that submit, links that are real addresses, content present in the markup.
