What I wanted to say is that the router is only one part of the puzzle. B2 was purposely made to do long distance FPV with up to 1000mW wifi power (crippled in most regions) and a decent sized MIMO antenna setup. The dobby and
Tello were made to be used in 30-50m distance and both carry wifi equipment that is adequate for this job but no more.
As a result you just can't compare the benefits of a router for the B2 with the benefits of a router for a Dobby or
Tello.
In a B2 + phone use case the phone is the weak spot. Add a good router that matches the qualities of Bebop's wifi and you will see at least 2-3km range (good conditions, no interference, clear line of sight).
In a Dobby + phone setup both are equal. Add the same router, and Dobby becomes the weak link. No way to get beyond maybe 800-1000m.
In a
Tello + phone scenario
Tello is the weak link. Add the router and it becomes even more obvious how weak
Tello is. No way to get beyond 300~400m.
There is only so much you can do without improving
Tello's wifi (which you won't improve unless you have RF equipment and know how). The only thing you can do is get into the antenna war: multiple directional high gain antennas.
But then its no longer all-purpose long distance FPV, but a "just stay in the beam!" FPV. OK for records, not for fun.
Yes, my B2 can do 3,5km on a "normal" router with almost perfect video stream. Done that a few times over open seas when following some friend's boats. I use a Xiaomi Nano Youth.
But thats by no means a record, I don't follow that closely but I guess around 5km or more is doable these days. That's a distance where the flight time becomes a restriction as automatic RTH can only do 10m/s and an RTH from 5km is about 10min flight time or 45% of the battery for a normal B2.