Thanks for asking and welcome to this excellent forum!
I ended up using Almased, a German product I got sent from the States. I liked it because it only had products I could identify in it. I also bought some whey powder from Nature's way, planning to blend it into soups and sometimes had pre-mixed protein drinks like Up and Go. In the end I also used some of the Optifast soups, Chicken and Vegetable, because I was so tired of sweet things. Post surgery I also used ordinary Cuppa Soups to help me get fluid in, even though they have little in the way of protein and are salty. I took those at times when the protein drinks seemed too much.
Watch out for the ingredients -- some of the soups have sugar (dextrose, maltose, fructose, corn syrup!) as major ingredients.
My partner liked the Tony Ferguson soups -- chicken and pumpkin. She also liked his coffee flavoured shake.
Hope this helps. It's a very worthwhile surgery, I feel.
warm wishes,