Let me be your glimmer of hope.
Scott Butchard, Senior Design Director at Rockstar, said something interesting to GQ Magazine, back when the Cayo Perico Heist released and was the first heist designed to be playable solo:
"We want to respect teams and players who want to play co-op. But at the same time still allow solo players to still get just as valid an experience out of it."
And:
"I think you can see that with Online and I think going forward we're going to inject more of that single-player element in there," indicating a future direction towards blending these elements.
Over the years they blurred the lines between singleplayer and online, allowing for solo sessions and making group content soloable. Allowing for online co-op of singleplayer content is not a stretch.