I saw some posts recently advocating for "evil characters" and "stop criticizing fictional characters like they're real people" and I've always had mixed feelings about that sort of thing because on the one hand, yeah, I'm not against fun, but on the other, there was also this idea of Arthas from World of Warcraft floating around a while back, portrayed as a poor little meow meow who is also played by Henry Cavil... and I really didn't like that.
And indeed, it does come across as a very snyder-bro attitude to have a lot of the time. You can argue in favour of complicated and sympathetic bad guys all you want, but there are no good examples of that, and the ones that are, aren't villains at all.
Zuko was often cited as a villain redemption done right, but upon closer inspection, he wasn't a villain, he was one of the protagonists. Even something as simple as Anastasia after the first Cinderella film, that worked because she wasn't a villain anymore, she basically got turned into a Shrek character.
There's also the simple fact that "bad guys" in real life aren't nuanced - ever. They're usually just insecure knuckleheads with shitty lives of their own making, who aren't doing anything fun, so they need overblown, fictitious boogeymen so they can feel better about themselves.
That means not only are bog standard megalomaniacs just more fun, they're also more true to life. You can chuckle at Maleficent for not getting invited to a birthday party, but people also crash out over nothing all the fucking time. If you go looking for a nuanced explanation, you usually won't find one.
Up next, there's also just the issue of "this wasn't made for me". See, activists trying to overthrow an unjust status-quo are right to do so. That's it. And this is only a problem for the cranky old shits who find having an obligation to the other people around them highly oppressive.
If you wanna write a sympathetic bad guy for me, the twist would probably boil down to something like "are we the baddies?" – they’ve been supporting an oppressive status-quo. That means it would be the protagonist who gets the redemption arc and switches sides completely. Call it the anti-6th Ranger, if you will. It's the only way the idea of a sympathetic bad guy could work.
When it all comes down to it, you're not looking for complicated villains, what you want is complicated protagonists.