My DP still has the E drive with 106 GB free.
1, You mean that your content library and package share are stored on E drive, right? (Please let me know if I misunderstand something.)
2, Please help check whether you have the latest security update KB5004442 installed on DP server? Someone fixed this error by installing it on all servers. The related link for your reference:
Issue with DP CWmi::Connect() failed to connect to Error = 0x800706BA - Microsoft Q&A
The error code 0x800706ba means RPC server is unavailable, the article about KB5004442 recommends us to verify if client or server applications in our environment that use DCOM or RPC work as expected with the hardening changes enabled. The related link:
KB5004442—Manage changes for Windows DCOM Server Security Feature Bypass (CVE-2021-26414) - Microsoft Support
Looking forward to your reply.