5 is a lot, but hopefully your eldest will at least be fairly self sufficient aside from technical glitches or the odd question, and a bit of chivvying.
My 3 are nearly 16 in gcse equivalent year, 13 and 9. The eldest is mostly self sufficient but a perfectionist and gets stressed out - last time she needed help with maths, physics and chemistry (taught in German, not my native language) which I had to do by watching tutorial videos with her as it was beyond anything I hazily remember doing at gcse! I did enjoy discussing her history assignents with her.
13 year old is self sufficient but lazy and just needs checking on and nudging/ chivvying.
9 year old needs a lot of help and gets an astounding volume of work - more than he can physically do in the time, all compulsory, accompanied by dire warnings about failure and slipping behind couched in very long waffly letters from his teacher. We had to pick up a learning packet yesterday - only option was between 2pm and 3pm, when I was at work (healthcare) an hour away! Good job we have 2 cars and DH could pick it up - we're rural, big geographical catchment, almost certainly some people couldn't get to the school during that tiny window of time with one day's notice!
The secondary school use Microsoft Teams which works well, but the primary use a local platform which is rubbish - and down, predictably. The learning packet directs the children to listen to a recording on the online platform in order to start the first activity, and the Platform is down - d'oh! This happened last lockdown too...
We're abroad and had full time tables for all the kids last lockdown too, so they're used to it at least. Last time I was studying for my own finals at the same time, and working 30 hours per week theoretically but actually more than full time due to colleagues constantly off, and it was incredibly stressful - essentially I had to do my own studying instead of sleeping, aside from trying to look engaged during the dial in compulsory classes which were frustratingly badly organised and unstructured yet compulsory...
This time its easier because it isn't new and we're only juggling with work, and no colleagues are off (touch wood!)