It was true for Elon trying to back out of Twitter's acquisition because tech valuations dropped significantly during the closing period. But this is Adobe and they didn't buy Figma for the memes nor did they roll out of bed thinking they should buy Figma that day like Elon probably did.
I think Adobe bought Figma thinking that they might have acquired Instagram. Today, Meta would be in a lot of trouble if they didn't own Instagram. Figma could have developed a suite of tools via their cloud-native stack and competed with Adobe across all of their products eventually. Basically, I think Adobe bought out their long-term competitive threat.
Quite frankly, at 9% of Adobe's total market cap, it's not that bad of a deal.