As of 8/20/2021, there is a new Verizon Messages app for Windows 10 in the Microsoft Store,
as reported in the 'Unexpected Error'
WooHoo!! but wait. When installing, it doesn't like the 8/18/2021 Message+ app on my primary device, saying it is 'out-of-date' and needs to be updated. There is NO newer update available in the Play Store. Unstalling (with reservations) Message+ on my moto z4 dropped from v8.0.6 to v6.9.8 and the v3.0.0 Win10 Message+ app installed 'successfully'. There is no SYNC option in the new Win10 v3.0.0 and no messages appear received after 8/12/2021. Reporting as bugs in the app.