I'm hesitant to write politics here because of how many people write scathing and rude comments, but I'll attempt to give a US perspective on the last election.
I think there were just a series of events that led to nobody getting excited by D in the election, allowing Trump to win. Especially when you consider that moderates and NPAs always decide the elections.
Inflation was out of control(by US standards) for Biden's entire term. In fairness this started at the end of Trump1 but carried on for years. Will Trump fix it? Who knows, I think most expect tariffs to make it even worse.
Immigration seemed unchecked, which itself probably wouldn't have been a huge issue, but news and social media 'investigators' came out about how much the gov was giving them - money, housing, healthcare, etc. Struggling and newly struggling people got really, really angry about money being spent there. That was a super easy play for R's all election season.
But the nail in the coffin IMO was the debate disaster, CNN turning on Biden as not fit to be president overnight, then last minute odd resignation letter via Twitter. Then injected with a candidate nobody had a say in, to boot.
So in short, a combination of people angry at 'the system' rebelling, and a candidate without much real support. I don't feel like R's won the election as much as I feel like D's imploded themselves. For the sake of not having an uniparty, I hope they rethink things. I feel like Newsom making a more moderate shift is a play in that direction, we'll see.
Just my .02.