I use both. For most services I use the service name in the email address. It's for me, not them. I get to see who its from, who sold my data or got breached, or who got bought and changed their name. If I ever need to tell it to a real human they always think its odd and I simply say, that's how I prevent spam and they light up because they are jealous I have zero spam (maybe 4 or 5 in the past 7 years and most went to my catch all)

For smaller services like my local pizza place, I use a randomized alias (I still put their initials in it to help identify it). The reasoning is that I have absolutely no trust that they have any kind of security on their website or janky payment platform, and I highly expect massive ad tracking from that platform. Side benefit is using burner email and phone number let's me reuse one time coupons.