Every few months I like to clear out my password manager of any accounts I don’t need anymore, usually just throwaway emails aliases.
I’ll usually attempt to log into any services that I know I’ve deleted/requested to delete to make sure they’re not accessible anymore and so far I haven’t been able to log in to any of them so I can only assume my requests are working.
I suppose if a service had a data breach, after my information was meant to be deleted, and I found my information there then I’d make a complaint to my regulator about not deleting my data. I would have proof of my request and their acknowledgement of the request so it’d be pretty silly of them not to delete it after saying they did
I rarely use anything but email aliases and fake information anyway and I never let online retailers save my card information. And if my address in on my account I change it to P. Sherman 42 Wallabyway Sydney before I delete/request to delete my account.