Some of the CZs are threaded and they are excellent along with the tikka

I shoot Tikka in base and it's a dead ringer. It shoots way better than I do. I currently have it paired with a Bushnell Pro scope. The scope is okay. It's on the better end of the scopes in base class, but it isn't phenomenal. That is where you see the real big different between base class and open division. I have an open class PRS rifle and my glass on that rifle costs 2 times what my entire setup in NRL costs together.

Of the ones you listed Ruger would be dead last by a decent margin. My daughter shoots one and it isn't very good. The only reason she shoots it is because it has a highly adjustable stock and it was cheap. She also doesn't shoot a ton or I would have bought her something better already, and honestly I still might.

Tikka has won the base class at NRL nationals several years. I actually shoot with the kid (young man now) who won it with a base Tikka. This last season is the first year he moved on from shooting his base Tikka to something else. His dad shoots his base Tikka now and the only thing they've done to it from the factory is sent it off to Lapua for ammo lot testing. The rifles just flat out shoot.

Both CZ and Bergara have great options that fit into the base range that come threaded. Just don't forget to factor in the budget for your scope. That is going to eat up a good portion of your budget as well.

I will warn you, don't get into NRL to save money versus PRS. It isn't any cheaper, it is a money sink just like all of the other shooting sports. It is an absolute blast though and the people are great. Also don't let the misnomer of Base class fool you. The competition isn't any easier. The level there is just as good there as anywhere else in the league. You also won't save money long term. 95% of the guys in base class end up moving to open division long term because they are unhappy with something about their base class rifle and want to class up. Most of the time it is either the stock or glass.