How to configure a block of IPv6 addresses that have been statically routed on CentOS7? - Codes Helper

I have a Dedicated server that manages remotely through IPMI. Recently, I asked for the IPv6 address through the administrator. Due to my lack of basic knowledge of IPv6, I encountered some problems in configuration, and the search was fruitless, so I came to ask questions. This is the reply I received from the administrator after I asked for IPv6 access

IP Range: 2604:881:39c::/48 has been statically routed to your server.

when I was configuring, I found that the administrator did not provide the gateway address. After consulting, I received a reply

This is a static route and does not include a gateway. All IPs are routed to your server.

I"m a little confused. I probably understand what it means. Because this is a physical server, everything has to be configured and managed by itself, including BIOS and installing the system from the mirror. I understand that the administrator has manually and statically assigned the superior route 2604:881:39c::/48 to my network card MAC. But I can"t configure it successfully. I randomly picked an address of 2604, 881, 39, and set 2604:881:39c::1 as the gateway. The configuration is as follows

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=no
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=eno1
UUID=6d049769-68a1-4631-83d4-46b0f3afdf59
DEVICE=eno1
ONBOOT=yes
IPADDR=XX.XXX.XX.XX
PREFIX=30
GATEWAY=XX.XXX.XX.XX
DNS1=8.8.8.8
IPV6_PRIVACY=no
ZONE=public
DNS2=2001:4860:4860::8888
IPV6ADDR=2604:881:39c::2/48
IPV6_DEFAULTGW=2604:881:39c::1
IPV6_PEERROUTES=no

when testing ping6 , it is as follows

PING ipv6.google.com(dfw28s04-in-x0e.1e100.net (2607:f8b0:4000:815::200e)) 56 data bytes
From myhostname (2604:881:39c::2) icmp_seq=1 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=2 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=3 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=4 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=5 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=6 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=7 Destination unreachable: Address unreachable
From myhostname (2604:881:39c::2) icmp_seq=8 Destination unreachable: Address unreachable

the DNS can be parsed correctly, but the public network cannot be connected, which seems to be a routing problem. I also tried to use ip-6 route add but to no avail.

does any brother know how to operate this? it feels like a very simple question.