I wonder about this topic so I want to send this idea out there:

I wonder how Mordred feels about her rebellion?

I think, like the many events in her short life, there's a sense of dissatisfaction about it. I don't think she believes it was 'wrong'. In terms of lashing out against Arturia, she'd probably consider it alright. But I think she wouldn't be happy with how she went about it.

She'd probably hate in hindsight how she involved the citizens in her petty vendetta, likely seeing a reflection of how her mother acted.

She'd probably hate ambushing Gawain and not killing him in a straight fight because, deep down, she admits she didn't prove herself better than.

She'd hate that she never made a good point against Arturia and wanted to make a true point against her, like an actual successor would.

And she'd probably hate that she actually killed her father, since even in death she was still bound to the throne.

I don't doubt in these senses, she'd consider the one act she made for herself a failure, even if she'd never admit.

This kinda reminds me of the fact that many people say Mordred doesnt really feel remors or guilt about the rebellion. Which I dont really agree with. I would say one of the reasons as to why she joined Lion King's side wasnt just to be the king's weapon, but also of guilt and inferiority.

Although not a perfect adaptation, but in the Camelot movies she states than one of the reasons she supports Lion King is that "idiots like her" wouldnt have to be born. Putting her inferiority complex and disgust for being Morgan's child aside, Mordred does feel guilt. It might not be as the same digree or fierceness as Lancelot, who is very vocal about his remors and guilt. But it is there. She has remors for not being able to save Artoria from her burdens, for involving civilains, maybe even for her existence itself, even if she would rather go back to the throne of heroes than admit it to anyone.

The Camelot Movies do a rather good job on expanding on Mordred's motivations, even if they are at best mediocre as an adaption.

Mordred definitely has more guilt and remorse about her Rebellion and the destruction of Britain than it seems at first glance. It was evident in the Solomon Chapter and it's evident in the Camelot Movies.

If I had to describe why she's usually not as self-destructive about the whole affair as say, Lancelot, it's because there's this air of resignation towards how everything went down. Mordred has this tendency to see her Rebellion as something inevitable and unavoidable for her, I.e. the moment in Apocrypha where Mordred thinks to herself in a moment of self-loathing that she was always going to rebel because Artoria's love was never going to be enough or in Tristan's interlude where Mordred refuses to accompany the other knights because of her instincts and saying that she and Artoria would likely have come to blows if she had gone along.

Camelot does show Mordred's self-destructive side of course when she sides with the Lion King, even though the latter is clearly intent on seeing her dead by the end of this.