A variety of aluminum alloys get used for chainrings .. a 7075T6 alloy is used on the premium end of the spectrum .
when I put together my Rohloff bike , I chose a stainless steel chainring . as the wear is all on that one ring
old bike I used steel chainrings too, but the modern shifting schemes have a different set of engineering details
where I am fine with a shifting of gears that is not instantaneous .. friction and just 7 speed , triple crank ..
I just try to avoid the overgearing syndrome
yes good to think of the actual gear-ratios and not just the number of 'speeds'..