I think there is a general contagion, but it's not a causative disease like people mistakenly assume. When we use disease metaphors for social phenomena, we're often wrong about the mechanism. For example, it's not a "disease" when an athlete breaks a record and others find themselves able to reach a similar level of skill, they don't magically acquire some new physical trait, they gain understanding and technique through observation.
Similarly, the rise in trans-identifying people (or queer people in general) isn't some social force or disease "turning people trans/queer." As acceptance grows, individuals feel permitted to express their internal identity. A "suicide contagion," if such a thing exists, operates in a similar vein, it's not that people feel compelled by suicide, but rather they recognize the possibility itself.
The crucial element of human psychology here is the knowledge that something is possible. It's not merely observing someone else's action that matters; it's knowing we possess that capacity. Whether this fundamentally improves lives, or merely manages suffering, remains uncertain.
It feels like there's worse actual problematic behaviors we'd be better off addressing first, things where people do take it as a sign to join in because it's been made acceptable or to conform to the herd. Consider political divisiveness, when one side performs a revolting action (such as mocking an opponent or marginalized group) and others follow. Or, for instance, people bullying others because they see another person targeting someone else and decide to join in. These are actual issues where the behavior is spread through others doing it rather through internal feelings. People can always try to rationalize these behaviors, politicians or bullies may claim they're just "saying what everyone believes," but that is rarely true.
I think addressing these broader pathologies should take precedence over focusing solely on suicide contagion. Yet society appears more invested in containing this single symptom than grappling with the underlying causes of feeling worthless or trapped.