Most companies I’ve sent data deletion request just do it, but when they start to argue I just hit them with most ridiculous bullshit while acting like the most privileged bitch until they do it my way.

Try saying no, see what happens.
Fearmongering, gaslighting, lawful threats, technical jargon and the word ‘rape’ are your friend.

Just recently when requesting GDPR data deletion from UK-based company (as a EU citizen) they also wanted to confirm my identity, hell they will.

I hit them with the fact that a person controlling the e-mail address can use their ‘Forgot password’ feature to take control over the account and access my sensitive data they’re in possession of or steal my identity using their own services. I also not so kindly suggested that I’ll report them so their security practices are investigated for the safety of the customers.

…they deleted the data without any further questions.

PS. Not sure about UK laws, but for GDPR: Always request confirmation of the deletion and the detailed steps they’ve taken to ensuring your data has been properly erased. They’re obligated to tell you that upon request.