Intermediary risk for overnight money via Neobroker

Hello everyone, the 100k state deposit insurance (per customer/bank) protects against the bankruptcy of the bank where my money is and I can prove it. With a direct bank this is clear. With TR/Scalable etc. the money is in escrow accounts at their partner banks. So there is an intermediate level, and with it a further risk: If the partner bank goes bankrupt --> the deposit insurance takes effect. It's all ok. If the neobroker itself fails (does not invest the money properly, poor records