Secondary Suggestions For A Newbie

Hello all! I just recently was gifted this game by a friend after watching and wanting it since it came out (poor gamer problems). I have mostly played the robots and love the game so far but wanted some advice on where to go for a secondary.

I have heard that there are some secondaries that can work against tanks and the armored robots, I remember a crossbow and exploding pistol? It would be great to have a secondary that could help deal with those rather than using up a stratagem slot for a rocket launcher would be very helpful!

If not, what are y’all’s favorite secondaries? I’ve been doing fine with the base pistol in emergencies but it’s naturally limited. Any advice is appreciated - hit me with your best shot, veterans!