Checked in my AX1800, netbrid installed normally:
root@GL-AX1800:~# opkg update
Downloading https://archive.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/package
Downloading https://archive.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/base/Packages.gz
Updated list of available packages in /var/opkg-lists/base
Downloading https://archive.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/luci
Downloading https://archive.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/routing
Downloading https://archive.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/telephony
Downloading https://fw.gl-inet.com/releases/v23.05-SNAPSHOT/kmod-5.4.164/aarch64_cortex-a53_neon-vfpv4/ipq60xx/Packages.gz
Updated list of available packages in /var/opkg-lists/glinet_core
Downloading https://fw.gl-inet.com/releases/v23.05-SNAPSHOT/packages-5.0/aarch64_cortex-a53_neon-vfpv4/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/opnwrt_packages
Updating database.
Database update completed.
root@GL-AX1800:~#
root@GL-AX1800:~# opkg install netbird
Installing netbird (0.24.3-1) to root...
Downloading https://archive.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/packages/netbird_0.24.3-1_aarch64_cortex-a53.ipk
Configuring netbird.
Updating database.
Database update completed.
root@GL-AX1800:~# netbird version
0.24.3
Did you complete step two in that tutorial?