Is the 10% taken from the value of each transaction on a remote work platform permissible or impermissible, given the lack of knowledge about what specifically transpires between the seller and the buyer?

We understand that your work is brokerage, bringing together buyers and sellers, or manufacturers and those who commission work, or employees and employers, in exchange for a commission. There is no harm in this. If one of the clients requests something forbidden without your knowledge, then there is no sin upon you. However, if you know that someone desires a forbidden transaction, then it is not permissible for you to facilitate it. If you facilitate it with knowledge of its prohibition, you incur sin, and what you take in return is ill-gotten gain that must be disposed of. If you were unaware of the transaction's prohibition, and you had already informed the clients of the necessity to observe Sharia guidelines and avoid what is forbidden, then there is no harm upon you for what transpired without your knowledge and consent.