How to seal a conduit with an underground cable?

Would you lay the cable without a conduit?

In the garden, unless there are compelling reasons against it, I would always lay underground cable without a conduit. Underground cables exist precisely for such purposes.

I thought it would definitely make sense so that you can replace the cable if necessary (in case it gets damaged by something) e.g. water, shovel, or other things

Without a conduit, we can't easily replace the part that is paved over anymore

What exactly should break and when? Nothing happens underneath the paving anyway. And if you do actually hit it with a shovel (and no, water etc. won't damage the cable in the next 150 years – brutal force is the only reason), you just repair it.

Would you lay the cable without a conduit? I thought it would definitely make sense so that you can replace the cable if necessary (if it ever gets damaged by something) e.g. water, spade, or other things Without a conduit, we can no longer easily replace the part that is paved another part of the cable goes through the flower bed

If the cable is damaged, the conduit is damaged too. Then you won't pull anything new through there either and have to open the damage anyway. Underground cable means underground cable because it can lie directly in the earth. Better invest in a warning tape for the route. That is buried above the cable (with distance) and warns you when digging that it will become equally expensive ;-)

How is the cable supposed to break under the plaster? And at the other spots you put in the protective tape, that’s enough if you dig there once.

And if you do hit it, it will be repaired.

It can break at the spots in the flower bed, for example, and without an empty conduit, it could no longer be replaced under the pavement

or water gets into the socket, or if there is a short circuit caused by other things, the cable can't be damaged in the process?

it can break at spots in the flower bed, for example, and without a conduit you couldn't replace it under the pavement anymore

or water gets into the socket or if there's a short circuit caused by other things, the cable can't be damaged from that?

If it breaks in the flower bed, it will be repaired there. A short circuit and water in the socket do not damage the cable.

But if it lets you sleep better, have it installed in a conduit.

it can break, for example, in places in the flower bed

No, it does not break. If it does, you break it yourself – using a spade. But then you also break the empty conduit including the cable.
... and you simply repair the spot.

or water gets into the socket or if there is a short circuit caused by other things, the cable cannot be damaged?

No.