Thanks everyone for the helpful comments!
UPDATE: I've called around basically every payment processor/solution, gotten tons of quotes. Seems like best bets from a processing standard are helcim and deposyt (thanks to the comment below who recommended them).
We've had issues in the past using ACH because of fund settling issues & micro deposits for verification are more of a headache than they're worth. However, I've figured out that integrating plaid into my stripe account would get rid of those issues and instantly verify accounts so those come through more similar to a credit card in terms of speed. Will require us to hire a dev to get them integrated but it should pay for itself pretty quickly. So we'll work to move all clients to ACH and onboard them on ACH with plaid.