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.

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.

I use Olauncher, pretty similar to Niagara and is FOSS. https://github.com/tanujnotes/Olauncher