Unable to route ports, ISP assigned private address - connection down issues every 4 hours

Solution 1:

1. Many ISPs in their basic contracts simply have a limited consumer internet user in mind and will purposefully break things for everyone trying to use their uplink as a proper internet connection.
   • You might be able to switch your contract to one geared towards hosting.
2. Many ISPs stopped caring about getting everything right for IPv4 users as soon as IPv6 became preferred and thus their carrier-grade NAT solutions for using their limited IPv4 pool will simply break everything but the most simple use cases.
   • Avoid CGNAT limitations by using IPv6: if necessary, configure your VPN client to prefer IPv6
3. Manage your expectation. 4G is not a cable: Phone companies expect that they can online/offline towers however they please because phones can generally deal with that. Atmospheric influence on 4G is only partly mitigated.
   • Because of the uplinks inherent limitations in terms of reliability, making sure your VPN client can swiftly reconnect and just living with the occasional latency spikes may be more cost-effective than convincing your ISP to become as reliable as few other 4G customers are willing to pay for