I think the answer is that it won't be normal school or teaching or anything close to it.
It won't be possible to run the usual classes with them having their usual teacher and socially distance. Therefore, as their usual teacher can only teach a smaller number socially distanced, that will probably go out of the window. As they are with different students for each lesson it won't be possible to do more than possibly 1 lesson with usual classmates in a day.
What might happen is large numbers in something like the hall (socially distanced) receiving info about 1 subject per day before going home - probably just getting 1 meeting per subject before the summer. This isn't teaching - it's information giving.
So school might specify 1 or possibly 2 subjects per day which will be covered and they would come in just for those and then go home.
The idea that it will be lots of lessons for each subject per week just won't be possible.
I'd suggest that educationally it might achieve less than remote learning, especially in areas where schools have provided decent remote learning, but now might be less able to if lots of staff are in school.
I think we have to resign ourselves to the reality that actual, useful teaching in person, as we know it,mis not going to be happening. It's a bit of a filler until the summer.
Currently there's a lot of moaning about provision from parents. I'd think the moaning will grow hugely when the reality of what can actually be provided becomes clear and lots of people might become more positive about remote learning rather than making the journey into school for a short period of something which really might not be very valuable.
Some independents are looking at 2 weeks of remote exams for the 2 weeks after half term, followed by 2 weeks in school for feedback (couple of subjects per day to reduce mixing) and then they will be breaking up as they finish early July. But they've been teaching live lessons and completed the curriculum they would have covered if in school anyway. The only things missed out on really will weeks of trips or enrichment type stuff which often come at the end of term.