If you want WPA3, use the current master. There the support works ok and also LuCI supports WPA3. Discussion e.g. in Wpa3 support in OpenWrt? - #91 by knacky
The support in 19.07 is not complete. @jow has done effort in fixing things in LuCI and the supporting packages in master, but some of those fixes (e.g. for rpcd, iwinfo) have not yet been backported to 19.07.