I'm trying to find what model my Bianchi is
At first glance I thought it was horrid cheap late 90s BSO that someone had slapped a Bianchi sticker onto.

But no - here's a similar unit:



This was found at https://www.picclickimg.com/d/l400/pict/254206275588_/Bianchi-mountain-bike-for-competition.jpg but the site has somehow disconnected the image from the associated text.  

I'd be hard-pressed to say which is the newer/older between this orange one and your one.  Both have old-style boots on the front suspension, which suggests late 90s.



The other find was a police auction website at https://www.propertyroom.com/l/bianchi-mountain-bike/12983885



Sadly this one has no useful details either.  This one has disk brakes, no stanchion boots, and is probably a much later model than the one above or yours.



Both the pictured bikes have both chainstays and something like seatstays, , whereas your one only shows beefy L-shaped stays holding the rear wheel.  This makes me suspect that your bike is the oldest, and the rear... fork (?) wasn't that good which is why later versions reverted to a separate triangle.

Personally I'd do basic maintenance, change the brake pads, clean it, and ride it.  The rear shock will be pretty useless after all this time (those shocks weren't very good to begin with.)   So just ride it.

There's almost nothing to be gained by knowing what model a bike is other than a general interest.  There will be no parts that are unique to this bike, other than the frame itself.  If you need a replacement part, take the old one to a LBS and ask for "one of these please"