Luggage for trains and flights - teens

[FallenFigs]

My DC are now teenagers, so I’d like to buy them luggage they can use themselves.

Our next holiday is to Europe on trains and a flight.

We also do cities, camping sometimes etc.

What‘a the best luggage to get them that fits this brief? They need to be able to manoeuvre it themselves, pack enough for about a week, fit it on most public transport and ideally fit on EasyJet as a cabin bag. also needs to be durable.

Any recommendations? Or types to avoid?

I am not a teen but I have this: https://www.amazon.co.uk/gp/aw/d/B07SM7B7VR?psc=1&ref=ppx_pop_mob_b_asin_title

It's light; you can fit loads in (I've done a week with it); the airlines let it on as underseat baggage; it's inexpensive.

Second the above, though I’ve got the slightly larger one but fits loads in and comfy as a backpack