Help Needed Creating Signed PDFs That Can Be Opened By Anyone

I have a PDF (non fillable) form that I would like to sign with a certificate-based signature versus the simple graphical signature available in the "Fill & Sign" feature of Acrobat Reader DC, i.e. a read-only document with a timestamped signature data field that the recipient can cursor over and see a "valid signature" message box.

Unfortunately, after a lot of research, the only way to place a "true" digital signature into a PDF document is to "secure" the document with my digital ID certificate, which is then embedded in the document. Creating a digital ID in Acrobat was very easy.

The problem is that the document securing process also seems to require knowing the public keys/certificates of the recipients, something I don't have access to, assuming they even exist.

Document securing also involves encrypting the document.  After more research, this encryption can be limited to PDF attachments, which will not be used, allowing the document to be viewable by anyone, leaving the problem of the recipient certificates.

The only workaround to this that I could think of was to simply use the certificates stored on my Windows installation--e.g.  "COMODO Certification Root Authority"--as the "recipients" since the actual recipients will probably have these certificates on their computers.

I wasn't expecting this level of difficulty. The procedure that I researched for signing Word documents also requires attaching a digital ID certificate, but lets anyone view the resulting timestamped, read-only, signed document.

Any assistance would be greatly appreciated.