Funnily enough I'm in the middle of creating a new Windows 10 deployment Task Sequence in SCCM for a client. Default browser is Chrome (which I hate, but it has ADMX templates so can be controlled) then Edge, but they still need IE for one ancient LOB app which will only run via an unsigned ActiveX.
I have pointed out the risk of this, but they wanted the ActiveX installed by default in the image, so the only way I could find to get this thing working is a batch script to copy the DLLs and OCXs to the SysWOW64 folder, then manually registering each of them as part of the script. The date stamp on the CAB file containing the files is from 2000.
Thankfully I normally only have to deal with ActiveX plugins on old servers where the DRAC or iLO still use them, and they are getting rare too.