Stripe no longer viable for startups experimenting with business model - Stripe does not allow Testing Standard accounts

I'm creating an app where my users will sell items to other users. Since I expect my users to have very low sales volume until the business model is worked out, I'm using Stripe Standard connected accounts (Express & Custom charge per user per month).

Unfortunately Standard accounts cannot be tested. You can create a connected Standard account in the test dashboard, however payments & payouts will be disabled. This is because a connected Standard account cannot be verified. Stripe will not allow entering test bank account or routing numbers into test Standard accounts. And I think it would be unwise to use a real bank account for a test Stripe account. Though it might be interesting to see what happens if I use Stripe's test card number to make a payment to my real bank account.

How does anyone test Stripe Standard accounts?

Over the past 3 days I've been on the phone with Stripe support and talked to one person who has been at Stripe a long time but doesn't know what Standard and Custom accounts are, another who doesn't know what Linux is, and another who kept disconnecting because her computer wasn't working properly. Their final conclusion was they'll have someone call me back later to sell me Express accounts. No thank you.

If there are no solutions to testing Stripe Standard accounts, does anyone have any suggestions for a better payment processor?