My very first BBA attack was after a rescape without doing something about the debris floating everywhere. When you take everything out, rescape, fill part way, empty to the substrate and refill very carefully there isn't much debris.
I am the world's worst fish catcher but doing a major upheaval in the tank with the fish in there isn't happening here any more.
You cannot see what you are doing either.
Look around for bins you may already have that a filter will hang on. Buy a sponge filter you can stick in the main tank a week before a rescape. Don't feed the fish the day before and the day after the job.