ACH settlement is getting faster. There's been a big push in the last few years, which will finish March 19, 2021 with three same day ACH settlement windows, and from what I can tell most (all?) ACH transactions under $100,000 eligible for same day settlement, with the remainder settling the at 8:30 AM Eastern the next business day (or future day if future dated).
What services banks and brokerages offer on top of that, can be more limited of course, but that's the state of the system.
What services banks and brokerages offer on top of that, can be more limited of course, but that's the state of the system.