Huawei Router behind a Mobile Company

You are apparently behind Carrier-grade NAT (CGN or CGNAT):

With CGNAT, end sites, in particular residential networks, are configured with private network addresses that are translated to public IPv4 addresses by middlebox network address translator devices embedded in the network operator's network, permitting the sharing of small pools of public addresses among many end sites.

You will need specialized software to be able to access the computer from the internet. Some such services are:

• ZeroTier
• ngrok
• Nabu Casa

You may also ask your ISP for a static IP address (often a paid option), which will make your router directly reachable from the internet.

Assuming you are behind CGN - which matches your description, a VPN can solve this problem, however you require a specific VPN function which is not ubiquitous - you need the VPN provider to assign you a real IP address. If you google "Static IP address VPN" you will find the kind of things you are looking for. They are typically slightly more expensive then a standard VPN.