Well, the basic problem for everyone is that we do not have all the modules looking for. It is not your fault. It is really hard to get them even with premium packs purchases.
If you use Molten the heat version, as you can see, the resistance is a bit lower in heat and stronger in energy and phys.
With energy torso the resistance against heat attack is a bit better
Now, the tradeoff will be the heat/energy caps in an inverse way which you need to compensate in an inverse way.
The torso it is not bad. It is a good one and I use that one too. Actually 3 of them.
You can use Nightmare if you want. It is a good one that can help you set up according to modules availability. I do not have one developed because no needed in the way I played but it is a great torso and players do not think properly about it because start as common.
Using Nightmare can free you up some weight versus current torso. Also, it will work like MPV with a little less of resistances and caps will be a bit different. It is a good item to be use.
About your current mech. Even with parts maxed out "my h/e combine are premium but close", your cooling will be decent, but energy regeneration will be too low.
Even changing a bit, still a bit low in energy regen. It will be somewhat ok in heat condition and energy cap will be ok to manage switches if have to but will need to play smart against energy mechs. They can drain 650 mechs in energy cap and 350 regen fast and no recover. Sure, resistance is low so phys mechs can abuse but it is normal for now.
HP is low and, in the future, will have to add modules to increase HP.
It is just you do not have the modules for now starting the game. That it is totally normal. I was like that even with less I had to survive in some way. I lacked those regular modules. The only way I got those regulars was using the achievements tokens grants and got old offers that use to come both energy and heat regular modules for 500 tokens or so and without them, will take much longer to move up.
Do not get frustrated and forget about the other players about what they have. Focus on your own progress based on your own play time limitations. It will help you play more relax not been worried of ranks or someone else better at this point than yours.
I never did and still don't and play relax for my fun.
NOTE: You have a decent mech. Focus in basic and target a basic rank that you can be stable until you get much stronger with other parts.
Reality: It is a transitory mech design. It won't be a top mech. Some parts will be useful at top. The mech can give you a particular. Even won't cross, people do not realize that advantage in some ways. You will know where you at and how much you can make to then focus in other mechs in the side.