First thing's first, I am so sorry for your loss
I can understand when you feel like this part of you is tied to another person. It can be very hard or not feel right to move forward. As for those Daddies who made you feel wrong, they were the ones who were wrong not you. Littlespace is meant to help you feel safe, and there is nothing wrong about that
If I may ask, do you have other friends who are littles? Or do you have little things you are able to do for yourself? There is a stigma/stereotype that every little NEEDS a Caregiver, but your littlespace is for you, and it is meant to help you cope. I'm not accusing you of depending on a Cargiver by any means, and I am not discounting how helpful it is to have one to be a support system, I would just hate the idea of you thinking that this presence would make or break your littlespace.
I am of course not a professional, but I would believe that processing your grief for this friend is going to be a process that will not be an overnight thing. That is ok. Feel everything you need to feel until you are in a better place about it.
As for littlespace in general, back to what I started saying. A good place to start could be getting comfortable being little either on your own or with other littles, lots of littles on here are excited to make new friends and talk about things that make them feel smol!
This is a safe place for members of the community, and there are articles in the resources page that discuss self care for littles. Things you could do for yourself could be watching your favorite movies or shows, playing with your favorite toys/stuffies, eating your favorite foods, wearing clothes that make you feel little, embracing your littlespace for yourself, maybe even have play dates either in person or online with people on here! That way, once you are able to just have your littlespace be your own thing, when the time is right, or the right caregiver comes along, it will just be a bonus!
I know I don't know you, or have all the answers, and I hope others can reply and provide their input. Just remember you were a little before this friend, and while it is absolutely ok to miss them, I am sure they were wonderful, don't feel like you can't be a little without them. If you are comfortable sharing extra context, by all means feel free to do so