my opinion would be to try and hire an independent developer that has or is making one already, that might be willing to partner with you, or be paid by you. aspects of their tech could be worked into your project, and they could receive a commission on profit. many may not be interested, but some, who are getting a bit longer in the tooth, might be. people such as the crystal security guy, maybe bret lowry from winpatrol (i see him advertising himself on linkedin for contractual work), there is that unhackme developer, and lastly .. the novirusthanks guy. i always wondered what beautiful tech these guys could make under the same umbrella. but any one of them might be willing to license an aspect of their blood sweat and tears to pick up another revenue stream. even if just one was interested in working with you, you'd have jump started you AV by a decade.
now brett lowry invested a ton into winpatrol and it has been developmentally quiet over there for several years. this says to me that sales couldn't pay the bills so he has temporarily (or permanently) moved on to feed the family. he might be willing to license aspects of winpatrol out to you. or you might be able to buy into it and become a partner. then your capital could help him continue with development. he is brilliant at making software, but he struggles with marketing.
