for Buyback Ethereum from market i'm placed the orderbuy in under $150-$100 because we don't know if Ethereum maybe sometimes make price corrections in nearly, and Ethereum in few year again can hit more than $5k/Ethereum
when the market corrects the only ethereum, the dump is always the biggest and when the market is a little ethereum it also rises very slowly, but your strategy to buy it back will be able to use buy orders at low prices.
ethereum has been rising at a high enough price, so I personally have no doubt about its growth