In theory you could knock the item off the build plate and into a bin by positioning the print head behind the part and then pushing.
However your build plate would need to have a smooth front edge, so no clips in the way.
You'd also want to have some delay to let the bed cool down before attempting this, and have spare belts on hand for the day the installed belt breaks.
A fan may work IF you can control it to come on after the part has finished printing, AND your printer will release a finished part given time. Also, your finished part must be strong enough to survive the impact and fall without damage, else what's the point?
Also, your effective print volume would shrink - there has to be enough space at the back to drop the print head behind the part using gcode, and then slide the bed backward until the part falls off. You couldn't use the back ~75mm of the bed.
Personally I always have to use a scraper and occasionally a light hammer tap, so a fan wouldn't do anything.
If I were doing this, I'd either pony up and buy one of those Creality belt-fed printers that have a rolling platform, and drop parts off the front. The CR-30 https://www.creality3dofficial.com/products/cr-30-infinite-z-belt-3d-printer or other manufacturers would have the same.
The other more homebrew option would be to consider where the bed ends up after job is done, and then have some kind of "wiper" mechanism that comes from the side and pushes the part over and off the bed. It would have to be low enough to get any brim and priming lines out of the way too. Since the printer probably can't control this, you'd be looking at an external controller like a computer running a print server, orchestrating the wiper and then starting the next job.
You'll also want a really big roll of filament, or a filament-out sensor so you're not printing air.