Back to Office (BTO) mandates are a tactic of quiet firing, when you want to create a negative work envirionment or choice which encourages employees to resign due to unwillingless or being incapable of relocating to a specific city. Many people ended up moving to other parts of the country for various reasons, including moving close to family.

All of the architectures I've designed use Istio, and existing architectures I've maintained used Istio or other solutions. What companies are utilizing Linkerd?

The move by Buoyant will only cause a migration to Istio, which is by far more popular

At the time of writing this comment, these are the following GitHub statistics:
istio/istio - 1k watchers, 7.5k forks, 34.5k stars
linkerd/linkerd2 - 190 watchers, 1.2k forks, 10.2k stars
linkerd/linkerd - 206 watchers, 519 forks, 5.4k stars

Do you have evidence of this, or are you just blowing smoke?