I think that if you buy this coin for a long time, then you do not need to wait for further price reduction, you can buy right now. But if your intuition tells you to wait - then wait a little.
Indeed, if you buy ethereum for long-term investments, it does not play a big role at what price to buy. It is clear that if it grows to at least its maximum, it will cover all expenses. The price at the moment already looks incredibly low, it is unlikely that the price will fall much lower.