I’d disable the VPN for the moment. Try opkg update before attempting opkg install $packageName.
More to your over-reaching issue: NTP server definitions are located in /etc/config/system. So is the time zone (zonename). Add some static IPs as a failsafe:
config timeserver 'ntp'
list server '0.openwrt.pool.ntp.org'
list server '1.openwrt.pool.ntp.org'
list server '2.openwrt.pool.ntp.org'
list server '3.openwrt.pool.ntp.org'
list server '104.167.241.197' # 0.openwrt.pool.ntp.org
list server '73.239.145.47' # 1.openwrt.pool.ntp.org
list server '142.147.88.111' # 2.openwrt.pool.ntp.org
list server '171.66.97.126' # 3.openwrt.pool.ntp.org
/etc/init.d/sysntpd stop && /etc/init.d/sysntpd start && date &/or reboot should do it.
ps/ OpenVPN? Really? WireGuard, man… wireguard.