In the UK, banks like Starling, Monzo and Revolut (and building societies such as Nationwide) have added a call status feature in their apps [0][1][2] that tells you if they are actually the ones calling.
[0] https://www.starlingbank.com/news/starling-bank-launches-in-...
[1] https://monzo.com/help/monzo-fraud-category/monzo-call-statu...
Yeah, this is a no brainer (and I think most banks let you verify via the app rather than personal info) to avoid the annoying uncertainty (but note my mother would not be able to handle that I expect)