Ask HN: Best marketplace payment processor that minimizes inter-user xaction fee

I want to build a marketplace where most users are both buyers and sellers for different transactions. For example, assume we have 3 users, Alice, Bob, and Casey. Alice buys a hammer from Bob in one transaction but later sells the hammer to Casey in a different future transaction.

Since users are frequently both buyers and sellers, I foresee withdrawals from the marketplace being infrequent with a single user not making any over long periods of time. During sign up, I would like each user to make a deposit (let's assume for $10 each, so in the above example, total of $30 deposited). This deposit would sit in the user's connected account at the payment processor. When Alice buys the hammer, Alice's connected acct goes to $0 and Bob's goes to $20 for Bob (let's ignore taxes for now, I know I will have to account for them). When Casey buys, now Alice has $10 and Casey $0.

Which payment processor is the best for this type of structure? Can I do something like this with Stripe Connect? Any idea what the fee breakdown is for deposits, withdrawals, and inter-user transactions?

Dwolla supports "Balance-to-Balance" transactions which seems to fit. I'm wondering how other payment processors compare.

I did some searching for other related Ask HN posts and I came across this earlier post (https://news.ycombinator.com/item?id=1493421) from ~10 years ago. I wanted to ask again since a lot could have changed since then.

TY