An extremely common configuration for a LR BR light gun is a BAT B dual port action with an ejector. Since most shooters are right handed, these actions are right bolt, left feed, right eject. It's very hard to be competitive in LR BR nowadays without the ability to run your shot strings quickly, and an ejector makes a big difference in speed.
A BAT B will make weight for light gun class with a Nightforce BR scope. An MB might be iffy but would work with a Vortex Golden Eagle.
The LRB stock that
@Alex Wheeler has is very common and an outstanding choice. They track exceptionally well because you can adjust the rudder to make it perfect.
The Dasher has given way to the 6BRA as the most common LR BR round. Either is competitive, but the BRA tunes to the same velocities with about a grain less powder. We think that reduces throat erosion a little and helps prevent going out of tune during a match.
I have heard complaints about the BAT
DS 3-lugs being a little heavier with bolt lift. A heavier bolt lift slows down your string. While a slower string isn't as big of a detriment with 5-shot groups, it is a bigger issue with shooting 10-shot groups. In order to maximize smoothness, my BAT B has the roller upgrades.
The Nuevo LR drop seems nice. It's smooth and has the advantage of having the lugs horizontal when in battery as well as some other advantages. Regardless of the action you get, have it treated with melonite. At least the bolt or the action. Having the whole thing in melonite also works well.
I like Jewell triggers. They just work without drama. there are other more expensive brands that are very nice, but I have seen some issues with those--though anything can have an issue.
There are other good actions for LR BR from others makers. I don't know much about those.
Make sure you have a good gunsmith for the build, and bias your decisions to what he prefers. There are a lot of good smiths and many post on this forum.