Nothing in that article mentions any kind of "fragility" in JWT's design - and the issues it documents (e.g. consumers overrwriting the signature portion) concern only extremely non-compliant (i.e. dodgy) JWT scenarios - which sounds like someone applying a bodge because they were forced to implement JWT because it was thrust onto them, usually because JWT is already so popular already - so it's nothing inherent in JWT specifically, but any kind of distributed, non-opaque and structured authX/id-token would suffer from the exact same problems - though I appreciate the textual-basis of JSON and JWT lower the barrier-to-entry-for-bodging compared to binary formats like ASN.1 (though I speculate that if we had to use a binary format today I think things would be a lot worse overall, due to second-order effects of using a binary format, e.g. relating to higher barriers-of-entry).