>How do I have no idea what I'm talking about?
You dismissed A/B testing as unnecessary. That is sufficient for this judgement. A/B tests mostly run on the happy path scenario of a customer: An A/B test breaks, the company is losing money at light speed.
The loading-related issues overall may eat 0,5-1% of the revenue. It is not something that should be an afterthought.
Lol, okay. I didn't know that every single customer was going to go through a tunnel as they loaded the page.
I didn't dismiss A/B testing. I'm just saying that, if the analytics don't load on the client, you should already have A loaded and ready to render. It's literally just a matter of a try/catch, and you shouldn't be waiting to load this stuff on the client-side anyways if this is truly supposed to be the "Happy Path".
Yes, I know that legacy software like Google Tag Manager requires client-side integration, but I would argue that is an orthogonal concern. You don't need to use that for your A/B testing. It's pretty easy to integrate this stuff into SSR-- especially if you stream in the HTML. This is why cookies exist.
And, again, none of this changes the central concept of this comment thread: JavaScript is necessary for the modern web experience.