Mentioned on youtube setting up a temporary sump with an intex pool to give u more than 1 days working time.
Worst case scenario for me would be to shut down for 1 day like ur thinking. I wouldnt mess with anything past draining the sump, throwing a new epdm liner overtop of the old one and getting it all back together. Realistically thats a tall order in itself to just do that in 24hrs. Moving the shade cloth media in and out and hucking an EPDM alone would take me out for sure lol…
I dont think its worth trying to kill yourself tho. Thats too much stress for 1 day. The massive amount of fresh water u add daily is ur lifeline. I think its doing alot more than u realize. If u can keep that going even with a much smaller sump. U can have plenty stress free time to work and do what u need to improve the old setup