Can MT6000 work as wifi client and host at the same time?

I have a scenario where ethernet RJ45 connection is not available but we need to have our own secure network so it is required that

  1. WAN connection will be done as wireless client
  2. LAN connection will be done as wifi hotspot
  3. Additional VLAN for guest wifi network
  4. router will be a client of OpenVPN or Wireguard to secure connection

Can this be done with Flint 2 MT6000 ? I know that if point 1 will be RJ45 then there are a lot of routers capable but I am looking for option where I can configure wireless client and do NOT want bridge mode to network on WAN as I need to have private LAN with shared printer that will connect wireless as well

Yup, going with repeater or extender mode will enable the Flint 2 to do exactly what you like.
See Network Mode - GL.iNet Router Docs 4

VLAN must be done manually and is more painful mostly.

like mentioned, I don't want to extend existing wifi network nor act as a switch to existing wifi network; I need my own wifi network and existing will serve just as wan connection for router so it can establish VPN connection

Repeater is exactly like that.
Extender would be a Level-2-bridge, but Repeater will be in WISP mode.

thanks, now I understand