192.168.x.x is an IP address range reserved for private networks. That is, nobody on the Internet is allowed to have a public IP address in that range, meaning everyone is free to use it on their private networks.
https://en.wikipedia.org/wiki/Private_network
If the gateway for your phone's hotspot is 192.168.43.1, that means your phone's carrier is assigning its phone users IP addresses on its private LAN, which then connects to the internet via a public IP address. Unfortunately this situation is going to become more common now that we've run out of IPv4 addresses.
The bottom line is that port forwarding will not work. Basically, your phone is not connected directly to the Internet.
It is sitting behind your phone carrier's main router on your phone carrier's LAN. And to successfully port forward, not only would you need to port forward on your router/phone, you would also need to port forward on your phone carrier's router. And they're not going to let you do that.
You might be able to accomplish what you want if you subscribe to a VPN service that gives you a public IP address. A VPN lets you tunnel your Internet connection. So right now, when you browse a website, your packet goes to your phone, then to your ISP, then to the Internet at large. With a VPN, your packet would be put in an envelope, sent through your phone, ISP, and the Internet at large to the VPN. The VPN would unpack the envelope, and transmit your packet as if it were being transmitted from the VPN. Basically it makes your computer look like it's on the VPN's network instead of your ISP's network.