Need an ai mesh node for range not necessarily speed

[Paintmaster]

Hello, recently purchased Asus GT-ax11000to replace my aging nighthawk r7000. The new router covers basically the same distance which covers my whole house and most of my backyard. My question is what would be the most economical ai mesh router that gets great range on the 2.4 end. Maintaining a connection behind my back yard in the field where I walk my dog is the goal here. All I need is a connection for web surfing and low res streaming so highest speeds are not necessary. For reference sake from my house to the back of my yard is about a 100, maybe 120 ft and than the field. All together I'm looking to get a stable connection about 300 to 400 feet away. Any suggestions would be much appreciated. Thanks
PS, I will have a great location for the node which will give me line of sight so there shouldn't be any obstacles in the way of the coverage

 

[Paintmaster]

Also for anyone interested I was hoping the new asus router would give me a little better range, but if anything it might be slightly less. Not enough to create a problem. That nighthawk was a beast when it came to coverage though

 

[Ichiban]

Asus 68U easily available and cheap for mesh.

I also upgraded from the R7000, and the R7000 was a damn good router. Too bad the rest of the netgears all suck.

 

[Grisu]

RT-AC66U_B1 is same like 68U but cheaper in different housing.