Vizio remote will not copy to my buzztv arc 100 remote any ideas how to fix this, it’s from a UHD Vizio smart tv

did you check this ?

Have you managed to copy any other remote ?  Just curious..

I can't comment about the more recent vizio units, but the older ones even shared some codes/overlaps with LG remotes, so the frequencies are not anything fancy.

I know I recently tried on an archaic "audiovox" TV (copying to the IR-100 from my E2), and it was difficult, but I managed to do it.  I realized that the audiovox remote would not continuously transmit the power button IR as long as you pressed it.  As soon as you hit it, it would flash for a split second and that's it.   So I had to point the remote at different angles and constantly press/release the power button, and if finally worked.  Just a thought.