Considering that Beto is just another radical open borders leftist... all in for impeaching Trump.... yeah. He would have been a disaster for Texas and for Trump. He would have been leading the way for RINOs like Collins & Murkowski to jump ship and vote against the Republican agenda. Does that answer your question?
As I said, a Senator's power individually is weak, but comes from voting in concert with others of like mind.
Since Beto would be in a minority position, it is not much power to have had by serving in the Senate.
As far as Collins and Murkowski, these RINOs will do what they wish regardless of whether Beto is a Senator or not.
Right now with the Kavanaugh vote, I would not place Collins in the same category as Murkowski. Collins came through while the other witch decided to burn some more broth for the stew she foments.