Mobile Hotspot 30GB monthly limit

I have an Unlimited Elite family plan with 5 lines. 3 of the lines/users do not use their mobile hotspot ever. 2 of the lines do. I am working from home and use my cellular phone data as a hotspot for work and to stream tv/movies to my TV. I have reached the 30GB limit and am being throttled heavily. Why is this hotspot usage measured per line when it’s a family plan and everything else is out of a collective whole?

I am confused as to why this is setup this way. So if all 5 of us lived at the same location we could use the hotspot to stream video (Netflix) up to 150GB per month (5 lines x 30GB). Since I am at a separate location I can only use 30GB. Is there any way to share between individual lines? I can watch the same exact content on my cell phone, full speed and unthrottled, but the act of sharing that feed to my TV is measured and capped. 
I am simply trying to find a way to watch Netflix and YouTubeTV on my home LG tv using my cellular data. I am not needing to share the Internet/hotspot to do anything other than watch the programming I can watch on my phone over my TV. I’ve tried using Chromecast but video streaming isn’t working using screen mirroring. Most of these techniques require a WiFi connection. 
Again, the only reason I’m using the mobile hotspot is so I can watch my programs on my large LG tv rather than my iPhone. Same goes for my iPad however. I cannot watch on it either because it requires the hotspot to get the feed.

Could I add a line for $10/month and simply get a second SIM card and swap out when my limit on one is reached, effectively doubling my limit by adding an extra 30GB per month?

Can I up the 30GB limit by paying/purchasing more bandwidth?

If the limits were increased by 15GB during the pandemic, so mine would’ve been 45GB and now is back to 30GB, did ATT not think people would want to find a way to keep this added bandwidth? Why back to 30GB, the pandemic is not over. Actually it has gotten worse and the US has had its worst day so far just the past few days. 
My ability to watch programming on my TV has effectively been shut off for the duration of the month as a result and I cannot watch anything unless I’m willing to hold and watch on my phone screen. 
Are there other options (cheap) I’m not thinking of? Of course I could buy a mobile hotspot, but at that point I could spring for WiFi. I am looking for a quick solution so I can watch some time sensitive programming like I’ve been doing for the past 2 years. I’m not sure why it’s hitting a limit all of the sudden. Probably because they dropped back from 45GB to 30GB because the COVID pandemic is.... over????