new user to maxis fiber business, was given 2 devices, 1 Huawei Fiber Modem and 1 Alxxxx black router, currently the VOIP is configured on the black router, is it possible to configure instead at the Huawei fiber modem instead as they have 2 VOIP port also attached

not too familiar with maxis fiber setup so asking here, is it possible to have setup consist of 1 unit fiber modem (maxis) with the voip attached to this main modem and router using 3rd party router..does maxis using 2-1 modem like TIME nowadays?

i believe this is Maxis own infra, located at Four Seasons, this is a business line..currently having this setup MAXIS ONU -> MAXIS ROUTER -> WATCHGUARD FIREWALL, recently the connection seems just down like that until reset of both ONU and Router, not sure what the issue, would like to get rid and just MAXIS ONU - > WATCHGUARD, , i believe ONU is HGH8240H with VOIP port but unsure why the VOP was tagged to the router instead(cant remember what model, black color one), possible to have the VOIP on the main ONU with bridge mode connect with my watchguard