Thanks for providing those details. You should be able to use the Apply Updates REST API to perform this operation. Please check if this works for you and let me know if you have any questions.
PUT https://management.azure.com/subscriptions/5b4b650e-28b9-4790-b3ab-ddbd88d727c4/resourcegroups/examplerg/providers/Microsoft.Compute/virtualMachineScaleSets/smdtest1/providers/Microsoft.Maintenance/applyUpdates/default?api-version=2021-05-01
If you still have questions, please let us know in the "comments" and we would be happy to help you. Comment is the fastest way of notifying the experts.
If the answer has been helpful, we appreciate hearing from you and would love to help others who may have the same question. Accepting answers helps increase visibility of this question for other members of the Microsoft Q&A community.
Thank you for helping to improve Microsoft Q&A!