I'm mining Ethereum and getting 57MH using NBminer and the power consumption is 167w, I noticed my 3070ti gets hotter if I mine other algorithms most especially that ravencoin, that's where the mem temp spikes up to 90°C, it scares me as I want this GPU to last longer
Well if you want your GPU to last as long as possible, maybe you should not mine with it. That being said, 90 degrees is still okay (especially if you're mining). Even if you're just gaming once in a while you might see that temp. Just take a look at GPU reviews and you can see that RTX30-series are hotter in general, so that temp is not surprising.
I'd rather focus to get ROI as fast as possible so even if your card dies, at least you make a decent profit with it.