Bob, welcome to the site!
First, there is no "best". We all have preferences for brands & models, based on what we do with them & largely due to personal choices. Some folks like specific brands or a particular model better than what others will like. Opinions will vary greatly, because we're all different. The best rod for you may not be the best for another person. However, there's no way to determine what might be best for you until you try a few different rods. That unfortunately is not always an easy task to accomplish. If you have any fly shops in your area, then that would be the best place to try out different rods. You may find you'll like certain brands better than others.
For myself, I own several rods of different brands & they all do what I want them to do. I really like TFO rods, because for me they feel "right". It's not a technical feature, just I'm very comfortable with casting them. However, I also own a couple of Redington rods & like the way they cast also.
Fly rods are no different than any other type of rod. No single rod will do everything. There will always be compromises. A 6 wt rod is a good choice to start with IMO for light bass & trout fishing. It may be too light for some large flies that are used for bass, and possibly too heavy for some flies used for trout, but is certainly in a category that fits with many situations for both species. I've fished for bass quite a bit with a 6 wt, and have used it for trout, as well as panfish & some saltwater species. In my area for trout or panfish a lighter rod is IMO, a better choice, as the fish are not usually large, & the waters relatively small, so I like a 3 or 4 wt rod better for chasing those species. I've used the smaller rods for some stream bass too, where the streams are very small & the bass will only be about 12" or smaller.
Choosing any fly rod is a compromise based on the waters, the size of the fish & the fly sizes we intend to use. Plus, of course budgets come into play also!
You might also want to see if there is a fly fishing club of any sort in your area. Most such clubs have members who would allow you to cast different rods & aid with casting technique. It's difficult for a new fly angler to really know what rod is best for them until they have some experiences with different rods.
I know this doesn't really answer your questions, but hopefully will get you going in the right direction.