I'm sort of half feeling sorry for them but half "you reap what you sow".
I feel sorry for them that the birtish media will now have a field day about them, with gossip accusations and lies. That can't be nice to deal with, they will be criticised regardless of what they do, they will be stuck in a can't do right from wrong situation. After all Harry is grieving the loss of his beloved grandmother and should be supported at this time, and given space to grieve. Meghan must be absolutely dreading attending the funeral, she knows no good will come of it, it's going to be awkward and she's likely to get snubbed. That's not a nice feeling to have, again she's only human.
But on the other hand, if they had just stopped talking, especially the OW interview and subsequent interviews/podcasts/publications. They would have ridden out the storm of leaving by now and there would have been a "ok" air about them returning. Less speculation, less negativity about them.
I think if they could go back and not say/do some things they would. But you can't go back in time. Despite popular opinion I don't believe Meghan is some sort of devil in a Dior skirt, I think she was a woman who didn't really understand what being a member of the royal family entailed, found it overwhelming and frightening. The loss autonomy over one's life is not an easy thing to give up, especially when you have been a "free American woman" for so long. I don't think she was fully prepared to weather the storm, the negative press and the massive pressure. So she left and Harry supported her to do so because he loves her and his children. There's nothing wrong with that.
What can happen now though, is the drawing of a line under it all, and I think The King has done that last night with his speech. He's shown support and love for their decisions, and a firm line has been drawn, it's time to move on.