There are great standard CMSes that do everything technically better than Wordpress (not that it's harder to jump higher than a rock, but hey). That's not the hard part. Every developer should build a good CMS once.
The hard part is displacing Wordpress market share; building a community of bloggers, marketeers, agencies, web designers, and so on; creating a huge ecosystem of paid and free plugins, allowing plugin devs to commit to your marketplace and lock customers in.
Wordpress is awful. The only thing it's got going is its moat, but that's not an engineering problem, but a people problem instead.
I find it hard to believe that people used to WordPress, with its flaws and virtues(yes, wordpress have virtues), will switch to this, no matter how much it's from Cloudflare.
Those standard CMSs that are technically "better" than WP, I would bet they are at least over a decade old, some have even come out during the same time with wp when there was no market share to speak of and still were left in the dust.
The problem is that people misunderstand why WP was and is better than all alternatives that tried to take it's place, I have no idea either but I know that others have tried same thing as CF and failed.
I have been one of the maintainers of a moderately successful CMS back in the day, but there are definitely well-groomed alternatives that have popped up a lot more recently than that, especially from the headless variety.
I'm convinced the thing that WP did better was being the first simple and accessible blogging platform when blogging was still a thing. IIRC, the alternatives were things like Joomla or Drupal - awful behemoths for enterprise users. WordPress was a breath of fresh air compared to those, and out of the blogging scene, people started to use it for agency projects, while others published an ever-increasing number of plugins and themes. The rest is just momentum of that movement.
CraftCMS for example is a great example of what you can achieve with PHP; there's Directus or Strapi for headless CMS, for example; or Ghost, Contentful, Storyblok and more as SaaS alternatives.
The hard part is displacing Wordpress market share; building a community of bloggers, marketeers, agencies, web designers, and so on; creating a huge ecosystem of paid and free plugins, allowing plugin devs to commit to your marketplace and lock customers in.
Wordpress is awful. The only thing it's got going is its moat, but that's not an engineering problem, but a people problem instead.