My first thought was the Agony in the Garden in the Rosary too, but what about the Stations of the Cross?
Admittedly, it has been a very long time since I have experienced that meditation, because it places us in His steps - I can’t imagine a more lonely place than the experience behind those stations, (despite being surrounded by so many people); to me it feels so painful and isolated.
Loneliness is, I think one of the most painful of human conditions - and one that we all must experience in order to have compassion for those who are also lonely.
And then I think about Mary during those terrible moments - the heartbreak and helplessness - she must have felt painfully lonely too - but then gratitude towards those who could (and then did) provide some relief in helping her beloved son along that lonely path.
I think a big part of loneliness is feeling helpless - so then finding a way out of that helplessness, sometimes through an act that we are able to perform … Mary couldn’t help Jesus with the cross, but Simon was able to … so he did … that act must have helped Mary as well as Jesus.
The culmination of that meditation, with Jesus in the tomb, (knowing what we know), that His glorious journey is now beginning, is a faithful path out of that loneliness. (I don’t think the phrase, “misery loves company” is accurate - I think misery needs company.)
(I’m sorry if this is so far off base of what you were looking for. Sometimes I get too immersed in the way things feel and lose perspective. I never stopped to think about this, but I wonder if this is one of the reasons that our churches have the Stations on their walls. I have never done them in the company of others, but I wonder if sharing the experience might make them easier to meditate upon.)