I don't think it's wise idea to invest in a coin only by looking the previous ATH, because there's no guarantee the coin will comeback or beat the previous ATH, it's not like Bitcoin.
Doge price was increase because Elon Musk trolled in Twitter and people take it as serious, so many people want to buy Doge. If Elon Musk stop to troll about Doge, Doge price will not increase a lot, just like in 2017/2018.
I totally agree with you that Dogecoin is not the right choice for us to invest because it has a very high risk. and we cannot refer to the previous ATH because not many coins have been able to surpass the previous ATH in the next BULLRUN. Dogecoin is just a memecoin that was raised by Elonmusk through his tweets so that it can reach $0.7. and what if in the future elonmusk tweets about another coin and not dogecoin.
If that happens, Dogecoin will be surely in vain aside from the fact that the coin is totally useless already as it doesn't have any utility that is why it's categorized as a meme coin but that coin will be supported or will be tweeted by Elon will surely gain a surge overtime as people will start buying that specific coin in the hopes that Elon will do his magic trick. But then again, the risks are not worth it as there are more chances that your funds will cease rather than seeing it gaining profits.