My anecdote: Collage.com - I tried it, was unsatisfied with the results so I requested that they delete my account under CCPA (being a Californian). They said they completed. My account was renamed from email@domain.com to email@domain.com-deleted12344843223432 . My session wasn't even terminated, so not only could I see this, I could still see my not-deleted photos AND all the sharing links still worked.
I fought with them at length and their support insisted it was deleted and that this was just something on my computer. Logout/clear cookies/cache/reboot and it'll be all good. I know that's BS.
Even when they "escalated" the issue to a manager who said "Your account has been deleted and will not be reopened." - I could still take screenshots of my account homepage. At which point they stopped responding to me.