I am so sorry to hear about your loss? What happened to Bruno? Sometimes a new bunny that is more outgoing, can help give confidence to a shyer or more reserved bunny. Since she had a companion all her life, she may end up bonding more with you in time now that she is alone, but for a bunny that has been reserved all these years, it will take some time. So really it could go either way, but if it were me, I most likely would just try and see how she would do with bunny speed dating at a rabbit rescue. I don’t know if they have that kind of service where you are located. I know it sounds rather funny if you have never heard of it, but basically you contact a rabbit rescue like your nearest House Rabbit Society, and they schedule a time in which your bunny can meet another bunny. The rabbit experts will have you tell them about Biance and based on her history and personality, they may pick out some potential matches. Then they have them meet in a pen. This is a really great way, with experts, to see which bunnies may fight (which they can prevent!) and which bunnies may hit it off, or have a better chance at bonding.
You said you adopted — did you adopt from a rescue? Maybe they would be able to help find a good buddy for Bianca. You can also say that you are looking for Bianca, but would like to see if you can find an outgoing bunny too — so it meets the needs of Bianca and you. They might be able to help to achieve that.
By the way — glad to have you back. What was your original member name?