They’re like 27% down from their IPO price two years ago. I don’t think their business has deteriorated so drastically that 17.5B would be attractive. I could be wrong though.
Yea, they've spent a lot of money over the last few years on questionable acquisitions (Weta for multiple billions, seriously?).
They are making a big push into their game services division, which is more than ads now: matchmaking, lobbies, dedicated servers (Multiplay acquisition), etc. They also aren't trying to only target Unity for some of these. Multiplay in particular runs a lot of Unreal games, or at least they did (such as Apex Legends).
Unfortunately I don't see a world where these services move the needle at all for a giant behemoth of a company like Unity.