Books? Coloring in? drawing? Audio books? Duplo? Magnatiles?

There are any number of alternatives that don’t involve a screen.

books are fine once you hit 6-7 years old, before then they'll get bored of them after 15-20mn since they can't read comfortably

colouring in / drawing great, but same thing, 15-20mn

construction games are great but they need to be carried about, they require space and there are parts you can lose

in places that aren't adapted for children (e.g. in an airplane or train), a tablet can be a life saver. you keep them busy/playing for an hour or so, then give them their digital crack for an hour, rinse and repeat. audio books are a good compromise

my kids have a personal music/story player (Yoto portable for those curious, it can be loaded with your own recordings if the cost of the licenced cards is too much).

The big one (5) has a camera, we also play guessing games (like the classic "animal, vegetable, or mineral" but usually specific to their interests such as animal, instrument, etc).

They both like books and will sit with them for upto an hour uninterrupted despite the younger one's inability to read.

After that, a switch, or a heavily curated selection of videos might be available.

I think screens are fine in moderation, almost all parents do it, but it's far from the only option.

> books are fine once you hit 6-7 years old, before then they'll get bored of them after 15-20mn since they can't read comfortably

Teach them to read young, buy books that are active, etc. My kids could read for a lot longer by that age, and so could I.

> in places that aren't adapted for children (e.g. in an airplane or train), a tablet can be a life saver

Talk to them, play games with them....

I loved spending time with my kids, and now they are grown up I am very glad I did.