Is the screen resolution 1366x768 enough for 15.6 inch laptops?

Is it possible to cope well with this resolution or should it be at least 1920x1080?

Much too little!

1080 in height is the lower limit, that's just decent HD, more is always good.

Yes, for common applications such as watching videos, surf, maybe even play a game that is more than just HD, HD is 720p, 768p is already over, that would be even the minimum resolution, less is not really so much joy.

but there may also be special applications for which the resolution is not sufficient.

768p is really out of date. Take one with 1080p, so you're well served.

1080p should be already. Mine has less and I can't operate a program, because the surface is too large, you can't change.

Full HD must be, everything else is Pixelpre.