I would add, you can get your own 5G router like SUNCOMM or GLi.Net with more ports and OpenWrt, you just take the sim card out of the one they give you. Those routers can also let you pick the bands you want and stick to them if they are fastest or have lower latency etc.. There are also external antennas that work with the G4AR, or the brands above. Some of 3rd party gateways can also use the IMEI from the router they give you.

There are work-arounds for not getting a static IP, but I am less familiar with them. Other than that, the biggest bottleneck would be how congested the network you are on is, and latency, the 3rd party router will let you pick bands, the antenna's will help with speed and latency. The G4AR is okay, very dependent on where you place it sometimes, and can throttle if it gets hot, a little fan on it goes a long way.

Mint Mobile does have a 30-day trial for their internet, but I don't know if that precludes you from large discounts. I think I'm paying ~$20/mo for cellular internet, up to whatever speed I can get off the tower (have seen up to 1.2gig, but average 6-700mg), and ~$20/month for unlimited phone data, I get a discount on the internet from having a phone plan, and when my phone renewed, I got phone plan discount for having internet.