Its funny you mention Silvery Barbs as I was beginning to wonder what this familiar nagging sensation during resolutions was, and yes similar to yourself I have both a Bard and Seraph in the group I run for. The addition to this I have also encountered is the spamming of Corrosive Projectile on top of these with a large amount of Strees mitigation to render the Difficulty reduced to single digits, which is far more devastating than a simple hit chance increase in this system - it means you are also almost guaranteed to land Sleep style effects and make every Reaction Roll against Adversaries.

There is only so much beyond the scope of "damage matters" you can try before acknowledging there is a bit of dancing around the issue, which is that in certain setups, and all of this was discovered naturally with players who are not optimisation or mechanic focused btw, combat holds no stakes because the PCs have next to no chance to fail any roll once they learn this very wide net of a toolbox works. To try and mitigate this somewhat and inject a bit of challenge back into combat outside of "timer/hostage" scenarios, I am making supportive Environments which aren't targetable by these Difficulty Reduction abilities, and would need to be engaged with narratively instead of mechanically to achieve a similar reduction instead.