I'm not really up on this field, so I've never heard of Keyoxide. Did a quick scan of your article, and a couple things popped into my head.
How old is this article? It references Twitter without so much as a wink to the rename.
I was under the impression PGP keys were no longer considered good security because the keys are static - i.e. they never change, which is why authenticator apps that change codes every minute have been all the rage for many years now.
PGP keys gain trust the longer they're used. But the likely-hood that they've been compromised also increases with time. I wouldn't say they get "less secure" with time. Also, you can very easily create a new identity under the same PGP key, and revoke a previous identity. Additionally, you can certify other's keys by signing it with your own, increasing the WOT (web of trust) with the key--asserting that the key does in fact belong to the correct person.
The keys are a bit more dynamic than you're giving them credit for.
There's also F/OSS which has been designed to alleviate some of the usability issues with PGP keys, mainly Keybase.
Hey there! PGP keys are still good and used by a lot due to they support the Elliptical Curve encryption and are still the backbone of Linux's repositories for verifying the authenticity of the debian link you're adding. In regards to your Twitter naming question, it's my own personal choice but I plan to deadname Twitter until Space Karen stops deadnaming his daughter.
Here's an article about PGP in 2025 in case you're interested!