Is the bonus granted by the forex company to the client, which can only be withdrawn after a certain number of trades, considered a loan that draws a benefit, and therefore, is this transaction permissible (halal)?

It is not permissible to deal according to the bonus because it is a loan with a promise of ownership, and the participant remains a guarantor of the bonus, which is reclaimed from him if the transactions are not completed. The company benefits from the commissions. This is a forbidden trick to engage in usury (riba) that must be avoided.