NAT (Forwarding) in T-Mobile Gateway

I was researching a project I was doing and came across this thread. I have T-Mobile @ home internet. The speeds are amazing compared to what I had prior to T-Mobile. On the T-Mobile router, I have three bars out of 5. I have on average 300Mbps ↓ and on average 20-45Mps ↑. I'm very happy with the speeds. However, I can't connect to my Home Assistant, security cameras, and my media center. I have an ASUS router that I have flashed with OpenWRT and I have tried several tricks, including doing DDNS updates every 10 minutes to my DNS server, CloudFlare. Nothing really worked. I spoke to T-Mobile technical support. That was just painful. I went to a supervisor. Finally, I had to state, "I'm a 4th decade computer engineer, I have the highest licenses from the FCC in amateur radio communication. And what you are saying is so horribly incorrect". I spent an hour teaching the supervisor. Finally, I decided to try their business internet. It was the same price as the home internet. Plus, for an extra $3.00 I could have a static IP address. They send me this Inseego router. It wasn't even a quarter of the size of the @home internet router. It was about 1/8th of the size of the @home router. Before turning it on, I knew this was not going to work. Surprise, Surprise, it did not! Most of the time, I had the blue flashing light, meaning I barely had a signal. Sometimes it would switch to 4G. When I had only one bar (very weak signal), I was getting 14 Mbps ↓ and 2 Mpbs  ↑. I found a spot in the house that I was getting three bars (good signal strength) and the speed was even worse. 8-14 Mps ↓ and 0.5 Mps ↑. This was not going to work. I cancelled the business account.
I did find a workaround. Or the best that is possible with the situation we are all in.
CloudFlare has a very generous free tier. I have many domain names. I have one that my entire family uses. CloudFlare has a very generous free tier on their Zero Trust feature. I use a Raspberry Pi Zero that costs $15.00. They're back in stock. If they are out of stock, they come back in stock very quickly. I have already received for this month (July 2023). I installed CloudFlared on the Zero W. Then in CloudFlare's Zero Trust I can set up sub domains to each device that I want. Home Assistant can have ha.familydomain.tld. Media Server, jellyfin.familydomain.tld, etc. Works with no problem. HOWEVER, there are two downsides. One, Zero Trust free tier does not "allow" and I use rapid quotes on allow. If you want to stream video, such as with your Plex or JellyFin Media server, you have to upgrade your Zero Trust plan to their $5.00 streaming service. However, as long as it's not to much, I heard they don't really say anything. But, technically, you could be cut off.
Second, is that I have a NextCloud server for my family too. When, uploading files to NextCloud outside your LAN, you can only upload a max file size of 100mb due to CloudFlare's restrictions on their network unless you upgrade. Even if you upgrade, it's not that much. That's the only thing that's really horrible with this alternative work around to T-Mobiles restrictions on port forwarding. Other than that, it works very well!

I'm going to create a YouTube video next week on how to set this all up. When I finish the video, I'll post an update with the link.
¡Buena suerte!