So, my instinct is that you (as a human) definitely deserve and need a break from bonding. Pancake will be fine, so try not to worry about her. I have been in your exact position and I know the feeling of just wanting to have them with a partner again, but you should definitely be kind to yourself and just rest. I think the time would be better spent working on the bond between you and Pancake than working towards a trio right away. I think in my own grief at times I just dive into bonding right away as a coping mechanism, and sometimes it works out, but other times it has been very stressful.

All of that said, personalities in trios are important, and the mix of sexes can also matter. I think since Maxwell was a bit of a wild card in the last trio attempt it could indicate he will be hard to bond with any other bun. If my memory is correct, he was also a bit tricky to bond with Ruby? I personally had terrible luck with my two females as well. I think if you eventually decide to try I would work with the buns individually in pairs rather than all three, and try a car ride or something stressful as the first dates. Prebonding will be important too, but Maxwell and Ruby may need to be separated during that time. So if you move Pancake down near them now, you could end up with three separate rabbits for a while.

So my two cents is that for now I would personally keep things as they are and just give Pancake extra snuggles whenever you can. I think you spending time with Pancake will definitely be enough for her for the time being (you could get her a stuffy as well), and when you feel ready to can make the call about whether you want to attempt a trio or look for another friend for her instead.