Should I move to Hyvä for performance?

If your Luma frontend is your bottleneck (slow LCP, big JS bundle, KnockoutJS-heavy checkout), yes, Hyvä gets you to Lighthouse 90+ for less effort than re-tuning Luma to the same level. If your bottleneck is backend (slow DB queries, OpenSearch misconfigured, Varnish not in front, third-party-script-heavy theme on a fast CDN), Hyvä won’t fix that, backend tuning will. The audit tells you where your time is actually being spent. If it turns out Hyvä is the answer, we have a separate Hyvä migration service, this performance project would be a stepping-stone or a bundle.