the answer for "Best Model" of any GPU is going to be the cheapest model that has a sufficient cooler. For the RTX 3070, as long as it has a good cooler, like the FE or pretty much any triple fan cooler, it will be able to perform almost identical to the more expensive ones.
I bought an RTX 2080 from a friend, the near top-line EVGA FTW3+ Ultra. I think it was about $200 more than base MSRP when he bought it new. It performs like almost any 2080 will, maybe 1-2% faster. I thought (and told him) he should have gotten a basic model for ~$150 less, and either ignored the very small performance difference, or do a slight overclock on his own to match it.
That being said, some more expensive GPUs will have slightly stronger components like power delivery chips, which is only very important for the SUPER strong GPUs, like the RTX 3090. The 3090s from the cheapest brands like Zotac actually had an issue, because they used a cheaper chip than Nvidia recommended, so they had instability problems. That was solved pretty quick though, and as far as I know, there were never such issues with the 3070 or even 3080 like that.