I’m running AT&T and Verizon tablet/phone sims in a Peplink Max Transit Duo bonded with Speedfusion.
I found that the best value for AT&T network is the prepaid tablet plan - surprisingly, I have had no throttling. It is a network managed plan and I don’t think I’ve bumped into it yet. It is fast for me.
I’m also using Verizon’s prepaid jetpack plan and I believe I’m being throttled since I run the sim in my Peplink Max Transit Duo router. I’m putting up with it because 1) my AT&T plan keeps me spinning along (both while bonded and as the first priority in my Peplink non-bonded configuration), and 2) I haven’t found another Verizon plan that I don’t have to pay a premium (see below).
At some point I’ll pay the premium price to overcome the limits above buy investing in a plan from one of the following. All of these plans are specifically tested for running in routers. Do a bit more research and you’ll find a lot of support for them.
There are many others that you can find with Google.