I guess it depends on the city. I found no lack of public restrooms in Zurich for example https://www.maps.stadt-zuerich.ch/zueriplan3/Stadtplan.aspx?#route_vi

I guess it depends on the city. I found no lack of public restrooms in Zurich for example https://www.maps.stadt-zuerich.ch/zueriplan3/Stadtplan.aspx?#route_visible=true&basemap=Stadtplan&map=&scale=64000&xkoord=2684543.7619809955&ykoord=1240666.0423263009&lang=&layer=Z%C3%BCriWC&window=&selectedObject=&selectedLayer=&toggleScreen=&legacyUrlState=&drawings= https://www.maps.stadt-zuerich.ch/zueriplan3/Stadtplan.aspx?... I found plenty of free toilets in Amsterdam and Copenhagen and plenty of pay toilets in Stockholm and Oslo. In Germany I usually looked for supermarkets, train stations, fast food restaurants, but come to think of it, Germany was harder.