Ok,
Thanks for all the info.
Situation is like this:
I have 1 Switch, playtime between my 3 daughters is split up (each get a change to play (unless there punished for whatever reason))
Now, with some action at a warehouse (get €20 voucher for each €100 you spend on multimedia/household and clothes (NOT Food/drinks)) i decided to buy a second switch for local multiplayer
I had a few other vouchers and bons, so i ended up getting stuff for just over €400 minus all the old vouchers i had, i payed €245 (for switch, splatoon 2, carrycase, glass screen protector and some clothes and a wierd Canadian softdrink to try out))
Cause the first total was just over €400 i got €80 in new vouchers where i can buy whatever again in the store, starting from next week)
So i think i got a pretty good deal out of it
Seems i will be setting up a second account, just like i did with my n3ds systems.
Both daughters need there stuff on there console, so both systems need to have access to the e-shop
Both have different taste of games (except for splatoon and mario kart), so those are the only games i have 2 times
The youngest daughter get to play on 1 (always the same) switch, she only plays splatoon 2 offline and mario odyssey (for her saves)
So an agreement is made wich my daughters to offer 1 to share her switch for playtime for the youngest (and that was more easier done than i expected

)
(I do not wish to buy a 3th switch, that's overkill and not forseen in my gaming budget)