Windows phones were really solid, OS was very user friendly and stable. I personally didn’t feel the “app gap” that a lot of others complained about but, I use my phone for browsing, calls & text. If I recall correctly it was also ahead of the curve with PWAs, integrated them really well. And price/performance was good on some models like the Lumia 650.
For me it was partially Windows 10 placing suggested apps and ads in the UI. The other part was just curiosity. After some distro hopping I landed on Mint, then Fedora and finally Arch where I’ve been for about two or three years.