Ok, well then this "3-days-per-week" solution will only be temporary on the way back to 5 days per week, because even this way, statistically you will only have

Ok, well then this "3-days-per-week" solution will only be temporary on the way back to 5 days per week, because even this way, statistically you will only have 60% of your colleagues present and will still have to do video calls. OTOH, you just need to have somebody from another office, or a customer, or a contractor, or ..., so meetings where everyone is in the same room will still remain a vanishing minority.