So, take everything with a pinch of salt, I may not be the best person to give advice, but regardless
I think the best you can make imo, would be
Core with SSJ Bardock and SSJ Broly with SSJ Yellow Vegeta on the bench to buff them. And then for the last core spot, I would just go situational tbh. I personally love Godku, and I think it fits well, he can deal with Yellowss that people bring to deal with your Broly(if they made Broly's passive end), and it's I think a great unit overall.
Black can be an option to deal with other enemies Broly(though I tend to deal with Broly's with my own Broly lmao). Kaioken Goku is also an amazing unit, though if your worried of having to blue or not having trinity worries you, you can ditch him out. And the lasst one to consider imo is Base Bardock, really goodd unit, ditches a lot of damage, a pretty decent ability. And then just for the other 2 bench sspots, just fill with saiyans Z-Ability to buff the core fighters acording to your playstyle. Personally I would go for ssomeone with strike passsive and someone with health passive.
In fact, now thinking, I would put Base Bardock on bench, he buff sstrike and you can bring him in certain situations.
Hope it was helpful