The majority of the banking industry is built on Cobol. Open Banking is the only real path forward. The issue of the US vs EU open-banking is the number of community banks.
The, unfortunate, most reliable banks from a technology/data perspective are ones that are large enough to be loathsome to deal with. Think JP Morgan, BoA.
Even banks of that size, Comerica, have had massive ledgering issues recently, so they are not immune.
Some reputable players in the BaaS industry are Unit, JP Morgan, Jack Henry, Moov(Massive plug for them), VGS (works with Visa and MC btw). If your neo-bank works with them, I would trust my money there. I do trust my money with one of those partners.