Which size kettlebells?

Hello guys!

I just saw, that at my Aldi Nord in Germany there will be Kettlebells on sale this week. 4 kg, 6 kg or 8kg (I believe this means 8.8 lb, 13.2 lb, 17.6 lb).

Now, I would like to mix up my training and include more kettlebell routines. I was able to try out kettlebells in my universities gym, but that was before covid, so I really can't remember which weights I used. But I do remember, that the kettlebell workout was SO MUCH FUN!

So I want to try to get some kettlebells at Aldi.

My question is: which weight should I get?

Normally I am very happy with my powerblocks sport 2.4 set, which goes up to 24 lbs per hand. I guess for kettlebell swings etc. a heavier weight is preferable right? So the 8kg one would be good I guess? Would it make sense to get one lighter one for upper body work?

Which size kettlebells do you use or would recommend? Adjustable kettlebells are not in my budget right now, but 1-3 kettlebells for 10€ each are possible :)