Hi Jason,
Greetings from Syncfusion.
We have already provided the support for showing the marker fill color same as the color of the Line. This improvement will be available in our upcoming Volume 1 Main Release 2022 which is expected to be rolled out at the end of March, 2022. Please find the below screenshot for your reference.
If this is your requirement, it will be available in our Volume 1 Main release. Kindly, revert us if you have any concerns.
Regards,
Swetha