wintertravel Schools here (Germany) returned 4 May (2 states iirc on 20 April)
The schools were discussing plans for several weeks beforehand with the local authorities & unions.
They got everything signed off
Both staff and students could choose to wear PPE - that reassured a lot of teachers, imo, especially those with health conditions.
It helps that school hygiene & facilities have always been pretty good, but there is frequent deep cleaning
As much extra money was pumped in as needed - because schools were an urgent priority
Schools mixed pt learning with online to get the full week
All forms have now rotated in at some stage
It doesn't help parents get back to work, but the focus was on the kids getting back to education and catching up.
Nurseries, kindergartens and childcare open too since 1 June - and will continue through the summer vacation
That at last has helped working parents
All that and no significant # cases in schools in all those weeks
Schools will probably open ft in late August after the vacation:
Opinion poll showed that 58% of parents want this, 34% don't
So probably attendance will be optional until EOY
Yes, I know that 9,000 deaths in an 83 million pop means people aren't so worried and also the German govt authorities have earned a lot of public confidence,
but you deal with the situation you have, govt cockups and all, not the perfect situation you would like to have.