Found that article I was talking about. Funnily enough, it's written by Evolving Wild back when they were doing some interesting stuff rather than trolling Twitter.
It's a little old now(written in 2017) and uses WAR, so it isn't ideal, but it does a pretty good job showing how players trend with age.
How do NHL players age? When do they peak? How quickly do they decline? Questions about player aging in the NHL have been debated for years, and an incredible amount of research has already been do…
hockey-graphs.com
As you can see, players tend to regress pretty hard offensively in their 30s.
Defense stays fairly consistent until 37 though.
I wouldn't be too worried about having Ekholm signed until he's 36.