Isn't TW the rolling-release variant?
Maybe I'm just scarred from years of IT, but I would avoid recommending any rolling release to someone if they specified "stability" and were likely fresh out of the Ubuntu/Green Ubuntu kiddie pool.
Just assume that they mean they want to set it up with minimal user interaction and then never, ever, ever have to change settings again.
stable ✅
technically comparable to Ubuntu ✅
not related to IBM ✅
doesn't feature snaps ✅
KDE plasma ✅
not DIY ✅
WCGW