I agree with MarkK, of the countries listed, Germany may be the one where you will need more cash than a bit. Many can do just fine, businesses geared towards international tourists will take card, but smaller restaurants may be cash only, laundries will need cash, paying for a regional bus ticket on the bus I found required cash. If you go to any festival and most street markets, cash is preferred to required for small purchases (many Germans would use a money transfer or app) similar with many beer gardens.
Like I said, you can avoid cash only places with some effort, but stray from the tourist path, it becomes difficult. I was probably more off the path than most for a month, plus 3 big fests, and found I needed about 200 euro a week.