Since Bitcoin and a few other Alts have been hitting new ATHs several times these past few months, would a massive 2017-like correction be likely?
In summary, it is very likely. Bitcoin fell below $11,000, a fall of 45% from its peak in December 2017, and continued to plunge even further. A BTC and ETH correction around 20-30% can't be written off but it likely wouldn't be as severe as 2017.
The current bull run is different because since 2020, a lot more instituational investors stepped up to the crypto market and bought bitcoin. The markrt went through a lot of resistance walls and many people recognized the true worth of bitcoin that they don't want to miss out on. Therefore the hodlers increased. I think we will rather see another run in the next few weeks, driving the price to 65k+. It's also very likely we could reach $200-$250k sometime this year by which time a big bear market might become inevitable.
Also, it is worth nothing that many alts are still nowhere near their ATHs. The future is looking good for BTC and the rest of cryptos and a steady rise is inevitable.
DCA might be your best strategy. Just pick a timeframe and invest at regular intervals regardless of the price.