I’ve set up automated monthly buys exactly like that in the past using Schwab. It was very easy. Though as int_0 points out, some funds have minimum purchase am

I’ve set up automated monthly buys exactly like that in the past using Schwab. It was very easy. Though as int_0 points out, some funds have minimum purchase amounts. The robo-advisors will let you do monthly automated investments but generally won’t let you choose what you invest in, only a “risk profile” (which ends up being a selection of investments not unlike a Vanguard target fund afaict). I also once had a 401k that would let you choose a fund allocation in advance (from a depressingly limited selection) and would auto-purchase with each payroll deposit.