I'm getting a similar issue but different scenario. My realm as of this morning didn't have any custom resources. I uploaded my first resource with the steps below, no issues:
Download resource and import to MC Windows 10
Download copy of realm and apply resource
Upload world back to realm with resource
However when I attempted adding another resource nothing seems to work as you mentioned. The first resource remains there and I cannot get the second one to apply. Whenever I download the realm again it shows both resources, but again, only the first one is activated.
EDIT: Also to note, I cannot remove resources from the Realm. There's no option in the settings and whenever I download an older backup the resources still come with the export.
EDIT 2: I tried your solution but on iOS instead of XBox and had no luck. Will try again on my XBox One later today.
EDIT 3: XBox One trick worked. Downloaded the realm and enabled the resources then uploaded it back and everything is proper.
Donut Run
I'm getting a similar issue but different scenario. My realm as of this morning didn't have any custom resources. I uploaded my first resource with the steps below, no issues:
Download resource and import to MC Windows 10
Download copy of realm and apply resource
Upload world back to realm with resource
However when I attempted adding another resource nothing seems to work as you mentioned. The first resource remains there and I cannot get the second one to apply. Whenever I download the realm again it shows both resources, but again, only the first one is activated.
EDIT: Also to note, I cannot remove resources from the Realm. There's no option in the settings and whenever I download an older backup the resources still come with the export.
EDIT 2: I tried your solution but on iOS instead of XBox and had no luck. Will try again on my XBox One later today.
EDIT 3: XBox One trick worked. Downloaded the realm and enabled the resources then uploaded it back and everything is proper.