In the arena of SPAs (Single Page Application) or React/Vue/Angular it's essential to know what server-side rendering is.
So, What is server-side rendering?
Server-side rendering is what you can say rendering in server.
Okay, But why should I care?
In this bright time of technology we just don't write HTML. It's the digital face of your brand. So you must ensure that everyone can see what you intended everyone to see. You cannot predict the end-user issues or what and what not that browser doesn't supports but for sure that browser supports plain HTML, CSS, so you should provide that as much as you can, to prevent unexpected behavior or an error.
How can we do that?
There are lots of frameworks out there, are just ready for use like Next.js, Gatsby.js. I personally like to use Next.js but every other framework is fine as well. It also provides code splitting and a whole other bunch of handy functionality. But with all of this, It's just making sure your powerful JS framework gives the most out of it, by ensuring server-side rendering.
Are there any other rendering methods out there?
Yes, as from previous you can guess that the framework provided JS functions can be run by and in your browser (which all updated browsers can just run fine) but ensuring the best user experience is what we frontend developers do.
So lastly, there is a lot of libraries and frameworks for you to make a difference, choose what works for you best and keep accessibility in mind and do good deeds.