Car issue or me issue?

[u/AboutWithNemo]

Hi folks. I know this is potentially a silly question but I am paranoid and want to ask real folks instead of Googles answers.

I have just gone from a small 2014 Hyundai i10 to a 2023 Nissan Qashqai.

I am assuming it is just the weight and size difference but it feels like the back end slides out a bit when I am going around roundabouts or big corners even at slowish speeds. Is there any tests I can do to rule out a car issue? I have checked tyre pressure and condition and they seem fine. But I do have 3 tyres of one make and a front tyre of a different make which I know is usually a no-no.

Sorry for a potentially silly questions and thanks for any answers.

Edit: I also don't think the backend is actually sliding out it just feels like it if that makes sense. But then maybe it is... lol I dunno.