It doesn't help that Microsoft does not embed the name of the party
who submitted an UEFI driver for signing in the signature itself.
Microsoft does do this; it's in an authenticated attribute with OID 1.3.6.1.4.1.311.2.1.12, aka "SPC_SP_OPUS_INFO_OBJID", it's documented as part of Office document file formats (VBA signing): https://docs.microsoft.com/en-us/openspecs/office_file_formats/ms-oshared/91...
The same thing is done for Windows drivers that they sign; Windows understands this attribute (binaries from specific parties can be blocked by the CiPolicy/SiPolicy which is Microsoft's current Windows-specific revocation list du jour), but UEFI firmware does not (yet).