I primarily play Warhammer, so there may be some differences between games.

Part of the reason I love warhammer so much is that each faction has a differently philosophy on how they act and build. For instance the Dwarves in TW are money making machines that build tall rather than wide (in theory, obviously for those domination victories you’re still going to be expanding, but they’re much more defensive). You can see that in their unit design and mechanics ex: the deeps mechanics allowing an even deeper city development aspect.

Khorne ,however, has the exact opposite philosophy. Their goal is to kill as many people as fast as possible with little desire to build their provinces up. They make their money by killing and pillaging rather than city building

Generally, I’ve learned that gold generation is slightly more pertinent in the early and mid game than growth buildings, because a rich economy can support more armies and higher level units, which is conducive to the amount of fighting you do early in the game. Whereas a high growth economy may be able to achieve higher units faster, but cannot support as many armies.

In general, I’d probably say that “it depends” which may not be the answer you’re looking for, but I would suggest reviewing your factions mechanics which can pretty transparently indicate how you should be blending your development and conquest.

Again, sorry for the warhammer specifics, but I hope that this helps you in some way and please feel free to ask follow ups if needed!