Or am I missing something?
I think the only distinguishing factor is to target, it must gather data. So that means your activity is being tracked, stored, and shared with third parties. Of course for some people this will matter more than to others, but for those privacy focused you now know for certain they are storing data on you, potentially making money off of selling it, with no way to opt out.
I just switched from linux mint to lmde 6 as well and it does feel very much the same cinnamon-y DE I left. The only difference so far is I had to install nvidia drivers myself as it doesn't seem to come with a driver manager like mint did. I've gotten everything else I used so far set up fine but... I guess I haven't tried gaming yet which I guess might be important to check out, will have to soon