It does depend on your normal pvp matches. In my case, I will max the energy modules at epic level including the resistance module. Heat is good for now and can L40 all of them as first step. Then change to energy modules and resistance. Due to require a lot of grinding, it will take a chunk of time to do so. If you farm enough every day and due 5 wins plus per day, you can get 2.5-4 million per week. With 5 wins and farming 4 set of fuel in full. You can end up getting 500,000 at least in the regular day and in 7 days it gives around 3.5 million. Leveling up one part from L1- to L50 on myth status, normally will cost 1 million not including the parts farmed you will require to have for it. That means, having L1-L30, L1-L40, L1-L50takes time and gold to transform epics to make legends. You have some months ahead to be able to do so.
For example I have some parts farmed to level up for L50 or easier for L30 or L40. Play titan, raid and war if possible. If want faster grinding, use last boss OD6 insane, if possible, for auto pilot or try a lower level like hard according your mech power capacity. Depending on BASE current status, I used to use L2 option RARE when I started with base to balance progress and enhance a bit faster with extra parts. It was too costly POWER KITS back then so RARE option was optimal for me controlling budget and when I was more powerful, then I enhanced a bit more the BASE to L15 for power kit option on factories.