Also in DK, the limit for being charged negative interest is generally 100,000 DKK ~ €13,500. With IT salaries it can become a monthly hassle dealing with it.
Probably why their Estonian branch was used to launder money.
https://en.m.wikipedia.org/wiki/Danske_Bank_money_laundering...
Most (all?) online banks I've seen will charge negative rates.
But ultimately the "if, how and when" is a commercial decision for the bank.
Some of them set higher cut-off levels (e.g. 50k vs 100k vs 1m).
Some of them segregate by account type (e.g. higher cut-off for retail clients than for business customers).
It might well be that some of them have a "fair-use policy" where they silently "eat" the negative rates but will quietly invite you to pay or move elsewhere if you have a large balance.