Have a look at the FAQ for datetime in the docs.mendix.com: https://docs.mendix.com/refguide/datetime-handling-faq#1-introduction
Your question gets a very practical answer in section 8:
I Really Need to Run Scheduled Events at 02:00 Local Time, Always! How Do I Do This?
Currently, you can work around this issue by scheduling 2 events that are running at 02:00 in both DST periods. In the Microflow you can check what DST you’re currently in and either execute the rest of the Microflow or not.
Hope this helps!
I experienced Daylight timing issue in Mendix 9.1.1 but this issue got fixed in 9.21.0.
Not sure about other greater version from 9.1.1