Are you primarily looking to use it for support for your 80-400mm lens? There are different features available on tripods so you will want to narrow down what is the most important for you.
For example, if you do any macro photography, you might want one that gets especially low to the ground. Some allow the center column to be inverted (so the camera hangs upside down close to the ground). Others have legs that splay out very wide while removing the center column and replacing it with a shorter column (also allowing the camera to be very close to the ground). And others allow the center column to be on a diagonal/tilted. Those with a tilting center column might be called some type of lateral arm tripods. There are twist locks for the legs or flip locks. Sometimes people have a preference for one over the other.
Height preference is also something to consider. A tripod is more stable when the center column isn't raised all the way. And that's why you may have seen photographers bending over to look through a camera's viewfinder.
Gitzo and Manfrotto are owned by the same parent company, but there are a number of well-respected names such as Benro. These 3 brands are ones I've owned which is why I'm mentioning them.
There is a less-known brand called Sirui (pronounced Sue Ray). Their waterproof carbon fiber tripod is rated very well although I don't know if their less expensive models are as highly rated. This one is their tallest and probably their most supportive.
https://www.bhphotovideo.com/c/product/1156937-REG/sirui_bsrw2204_w_series_waterproof_tripod.html
Some tripods come with heads and others are only the legs. Personally I prefer to choose my own head. And choosing your own head will be another big decision for you. As Dan mentioned, the gimbal head is quite popular for supporting long lenses. Since I don't own one, I have no idea of their weight. But you will want to factor in the weight of the head as well as the weight of the legs.