This is my personal take. If there is something that you can enjoy while playing the game. Then you should do that. If that means buying the upgrade then do that. If you would rather wait, that is also fine.
Personally, I am sitting on a tiny cache of Low temperature diamonds that I still can't sell at even a reasonable value because Fdev do not have any employee's capable of working their code infrastructure. Proof of that is that they took over 3 weeks to fix it while leaving the game completely broken. The only solution, give Fleet carrier owners some free fuel. While everyone else were completely not worth a moment of their time. To me, this means the game isn't worth playing. This means that Fdev isn't worth respecting, caring about, or even interested in supporting. Incompetence does not warrant respect, and respect of a company is earned not granted.
I never cheated. I never exploited. I never mined in some massive wing. I spent hours and hours of my life expecting a measured outcome. That outcome was then thrown into the garbage heap by Frontier to thwart the people who milked the exploits. That is how they treat their customers. They don't punish the people who took advantage of a system. They punish everyone.
So yeah. For me, this game isn't fun, engaging, or interesting. It is purely just designed to waste players time and to keep as many active clients possible so they can leverage those numbers to banks and such. This game isn't supportive of the player. It is only designed for their stockholders.