It would be less busy and less busy if you came for the earlier dates. I just checked two of the many places we have stayed in Venice, one an apartment and one a hotel, to see how the prices differed for the two datespans.
For arrival Feb 25, this apartment is 100€less per night than arrival 2/28.
https://veniceredhouse.com/apartments-in-venice/the-lions-house-apartment-lion-4/
For the same dates, this hotel is €80 less for the earlier dates.
https://www.lacalcina.com/
If you are at all interested in an apartment, I highly recommend the Venice Red House over trying to figure out owner rentals like Air BnB. The owners of VRH are Venetians, and they hire Venetians. Their apartments are carefully vetted and maintained. Their representative meets you at the nearest vaporetto dock and escorts you to the apartment to turn over the keys and explain the trash collection, etc. They offer support anytime you need it. I regard this as a very reliable company and book Venice apartments either with them or with Views on Venice ( which is generally more expensive).,,
I have read of or experienced too many issues with Air BnB rentals in Venice to recommend that route. Several times we have rescued upset tourists who could not find their way to the apartment using the instructions provided by the host. It sort of became my hobby when we were there for a week in March 2023.
Worse yet, during popular events like Carnevale, there have been reports of bookings being canceled at the last minute. Consumer advocates who investigated found a number of these instances where the host canceled and then offered the apartment at a much higher price to other clients. This was particulates with bookings around Taylor Swift concerts, but I can see it happening with major events like Carnevale with unscrupulous hosts.
But there are many lovely hotels in Venice as well, and they offer advantages such as breakfast, help with arrival, maybe concierge services, and above all a friendly face at the desk to greet you coming and going. Many people regard this as a safety factor as well, although I consider Venice a very safe place overall so do not worry about that.
The trick with hotels is that you will get so many recommendations it can be hard to make up your mind! But location, price and type of decor ( modern or traditional Venetian) should help you narrow it down.