You are searching for FOSS apps. You are a minority. There is no incentive to make AI lie about whether or not an app is FOSS - it’s just not a selling point to the vast majority of people.

However, AI is incentivised to give you an answer that it “thinks” will make you happy. That’s one of the reasons why it lies all the time.

I came here to suggest MX Linux w/XFCE. I use the plasma flavor mostly now but I’ve been using MX as my daily driver for like… 2-3 years now.