That’s just wrong. Revolut, N26 and Bunq all have banking licenses, which means funds are insured to €100 000, €200 000 if it’s a shared account.
It’s not that they “steal” your money, but unlike your local bank, their customer service is much less tactile which means that if you’re up shit’s creek getting out if it gets much harder.
The FDIC insured bank which actually has money when using these apps is somewhere in the backend and you get stuff like the synapse bankruptcy[1]
[1] https://apnews.com/article/synapse-evolve-bank-fintech-accou...