It’s easy and it started with that.
Edit: The services I’m talking about have fees. Barrier to entry prevents knowledge and usage. There are hundreds of services that provide this, all to different degrees of quality. But you could just Google “UTM Generator” and, assuming you set up a free GA4 account and set it up on your site, congrats, you’re now using cookies to track purchases based on link clicks to your website. Very easy and literally free.
I did one once where it was like 400 toggles. Took me 10 minutes. I did it just to see how ridiculous it was. I don’t remember what site it was but I definitely never went back.