Stephen Elop is widely blamed for the downfall of Nokia a few years ago. A Finnish book, "Operatioo Elop" has recently been translated into English and is available for free, now called "Operation Elop". I've not read it yet but it's generally considered to be a well-researched, well-written and balanced assessment of Nokia's phones and devices business's last few years before it was sold to Microsoft.
I won't post a link, but if you do an internet search for "Operation Elop" you'll find it.
Yes, some decisions, with hindsight, were perhaps poor. But that's the benefit of hindsight. At the time the decision makers have to take into account what they know and combine that with their judgement.
So, now you can read the book and make a more informed opinion about who was to blame for Nokia's fall from grace.
I note that Stephen Elop is rumoured to be a stakeholder in Smart Connect LP, the private fund that backs HMD Global. Whether he was to blame or not, lets hope that all the lessons from the past have been well-learnt and the same mistakes will not happen again.