Wireless Joint

So I am currently on a AT&T plan the "AT&T Unlimited Plus Multi Line Plan" and the current router that I have is the Mf279, im looking to upgrade to a better hotspot router and im having trouble finding everything I need to be looking for. (I was told this would be the place to get help)

Ive been looking at a few different routers but im not really sure which one I should be looking at. Im on a pretty tight budget and I really want to be sure it is going to be worth it to purchase a better router. Currently im getting 102dbm with this router and I have it mounted to a window and im using an either-net cable to my pc, Im getting 7mbs on download and 15mbs on upload and its 10:30pm here.

Ive been looking at the NETGEAR Nighthawk M1 4G, NETGEAR LB1121, and the Cudy AC1200. Im not 100% sure if my plan is 5g capable but my phone is saying that it is running on 5g and it is on that same plan as my hotspot router.

I know the plan isn't available anymore but I have been grandfathered into the plan that im on, I also called AT&T and I asked them if I bring my own router in that I bought that they could put a sim card in it... so, is it worth upgrading to a new router or should I just keep this router and work with it?

Please if there are any suggestions about routers or what I should do I am completely open to it, im not completely informed on all of this stuff so thanks for any help I can get.

The M1 can be the lowest cost for the most performance if you have a straight drop in hotspot SIM card, but I wouldn't buy any used ones. Most are Blacklisted by ATT; or at the least get a guarantee on it and an foolproof way to get a refund if needed.
Otherwise I would go with a modifiable openWRT based system fromThe Wireless Haven

Your budget is going to determine the level of equipment. If you want 5G, you are looking at $500-$600 and up.
The MF279 I believe is cat3 or cat4, so pretty much anything cat4 and above will match or beat your MF279 performance in most cases.

Well, I bought a pre owned M1 from Mercari last night and hopefully its not black listed, their policy states that if the product does not work I can receive a refund on the product... hopefully I made the right decision.