Something like the underlying account(s) used by the FinTech are secured in this way, but your account with the FinTech is not.
This is why Revolut for example have accounts which are something like "vaults", which are in fact accounts which are covered, because they are actual accounts, one per person, with a normal bank.
That sounds incredible, it needs to be checked, about to leave the house so can't right now.
Edit: and apparently they’re now setting up a bank in the UK as well: https://help.revolut.com/help/more/legal-topics/is-revolut-a...
Wise is not, and it might be more difficult to get the money out if they are insolvent. For the customers in the EU, they’re a Payment Institution in Belgium: https://wise.com/help/articles/2932693/how-is-wise-regulated...