Thank you for the answer.
I guess in the mean time it is possible to give a try of openwrt 19 and see how stable it is and later on change back to the original firmware or wait until new official firmware release.
I have the router integrated as part as a home network with two archer-c7 running openwrt too but 19th release, and the Slate integration was very easy, I have tried as a router, also as extender, vpn, tor, … I did not notice any shortage of connection or disruption and have excelent mobility as we even gave a test in other public network.
Thank you.