I’m using a Sectigo OV certificate, which I purchased through https://www.ksoftware.net/
Requires Microsoft’s signtool.exe to do the signing.
On my computer, it’s located here: C:\Program Files (x86)\Windows Kits\10\bin\10.0.19041.0\x64
Signtool uses the Safenet client, which came with the certificate.
It was a real pain getting certified by Sectigo – took around 3 months.
Cheers,
Lex