We do not use WMS but we use W10IoT thinclient with SCCM CB.
For UWF you have two options
1. You can set Windows update service to manual, create a specific “green zone period” to disable UWF for monthly for a few hours. Run a script to start Windows update service during the “green zone period” download/update/reboot/winsxs cleanup the device. And then turn on UWF by the end of “green zone period” .
2. If you want keep Windows update service running, you do need to setup UWF exclusion carefully and ensure that UWF has enough space to hold the download and commit all the changes.
There is a very good Japanese article about UWF exclusion if you want to run winsxs cleanup with UWF enabled
https://blogs.technet.microsoft.com/askcorejp/2017/11/06/uwf-setting/
PS. my shop windows 10 IoT devices are all coming with at least 8GB ram with 2GB UWF ram overlay configured
