u/JleHuBbluKoT

All lifestyle needs belong to a named category, for exaample, farmers and engineers have "Health" group of needs, but none of the needs provide reductions to illness chance.

The lifestyle tab is a powerfull tool, i have seen mods implement alternative consumption, so it must be easy to provide some other effect, like happiness or incident reduction.

Right now it is just extra pops and money, which is usefull, but samey.

My manola has 8 bauxite mines. I have built 2 bauxite mines, 18 aluminium smelters, and 6 sewing machine factories, these buildings cover as much area as a small island does.

To solve overabundance of aluminium i first built research institute to change the excessive bauxite deposits to gold, which i found out later is not possible in vanilla.

To utilize them all i would need to dedicate half of an island to smelting it... to then produce sewing machines more expensively, with more labor, and with a larger footprint.

How do i properly utilize bauxite? And helium, which is abundant too?

Items in this game are op. Replacing inputs, extra outputs, less infrastructure, they trivialize the game.
I play with the following self-enforced rules:
Global population: 100'000 for green, 250'000 for blue, 500'000 for purple, 1'000'000 for gold
Island population: 2'500 for green, 5'000 for blue, 25'000 for purple, 50'000 for gold.
As a result, i am forced to diversify large islands to use good farm items there, and to have densely populated small islands to have great ore output, and medium islands is where production happens.

What are your rules to limit powercreep and keep the game challenging even at later game stages?

If it is not possible to turn Baldarak, the home-gas-giant of Dathnak people, into a star via nomad contract or manually as a nomad, then i will stop playing stellaris forever in the history of universe.