I wish I had read this earlier today. I wrote my own mini-Cliff-notes on how to do things in SVG that covers a lot of silly SVG things in a Stack Overflow answer...

https://stackoverflow.com/a/54462467/3917602

The real problem with SVG is that you need to be a techie type rather than a paintbrush wielding type to get the most out of SVG. In companies this is forbidden. You can't have a techie do design. So you have to have off the shelf bloated 'assets' because that is how they come out of Illustrator. I find I always have to roll my own even for the simplest things such as the 'moon' icon that I thought worthy of putting in to a Stack Overflow answer for 'future reference'.

Clearly I will be watching every CSS-Tricks video on this series and I hope that this gets mentioned in it:

https://jakearchibald.github.io/svgomg/

This allows you to spot 'obvious' optimisations.