Question about Huawei B525s-23a

There is no problem with port forwarding. It is impossible to use port forwarding with 3G/4G/5G because the router has no access to the internet. Each phone tower functions as an independent router so you have to enable port forwarding for each tower and this is impossible.

https://superuser.com/questions...

Unfortunately, my French is too bad in this subject, so the answer is in German. Yes, DynDNS and port forwarding do not work when using the B525 with a SIM card. The problem is of a basic nature - see here for details:
https://dyn.com/blog...
There is, however, an ingenious solution - at least if you can use a Raspberry Pi as target system or jump host.
https://www.pitunnel.com/
Works great with the B525 router! Greetings, Wolfgang