如何让 Docker 为 qBittorrent 分配独立的 IP 地址和网关

家里用 N1 （ 192.168.123.115 ）做了旁路由网关手动设置给部分设备 FQ，Docker 运行在群晖（ 192.168.123.114 ）上，群晖的网关设置为 N1 IP，现在想跑 qbittorrent 下载 PT，由于不想 PT 流量走小飞机，想给 Docker 上运行的 qbittorrent 分配独立的 IP 地址和默认网关(192.168.123.1，DHCP 下的默认网关），尝试配置了下 compose 文件，但一直提示：

root@DSM:/volume1/docker# docker-compose -f /volume1/docker/qbittorrent.yml up -d
Starting qbittorrent-compose ... error

ERROR: for qbittorrent-compose user specified IP address is supported only when connecting to networks with user configured subnets

ERROR: for qbittorrent user specified IP address is supported only when connecting to networks with user configured subnets
ERROR: Encountered errors while bringing up the project.

由于不太懂 Docker，还请大佬指教下是哪里出错了

附上 docker-compose 文件内容：
version: "3"
services:
qbittorrent:
image: linuxserver/qbittorrent
container_name: qbittorrent-compose
environment:
- PUID=1000
- PGID=1000
- TZ=Asia/Shanghai
- UMASK_SET=022
- WEBUI_PORT=8080
volumes:
- /volume1/docker/qbittorrent/config:/config
- /volume3/Media/download:/downloads
ports:
- 6881:6881
- 6881:6881/udp
- 8080:8080
networks:
bridge:
ipv4_address: 192.168.123.68
networks:
bridge:
external:
name: qbittorrent