If you file a tax return as married filing jointly, you are only allowed to change to married filing separate status up to the filing deadline (April 15, or October 15 if you have an extension). If you already filed for 2023 and don't have an extension, it is too late to change. (This has nothing to do with your international status, it's the same rule for everyone.)
If you want to file separately for 2024, that's fine. Filing a joint return once does not commit you to filing jointly forever.