There is nothing to worry about OP even 90°C on memory temp for 3080 and 3090 are extremely safe, I'm even jealous you are getting just 82°C on your 3070ti that's a silicon lottery winner there mate, by the way what algorithm you mining cos all 3070ti are all LHR
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