upx is not used in the macOS build (we only mention it as a possibility in https://tailscale.com/kb/1207/small-tailscale/ https://tailscale.com/kb/1207/small-ta

upx is not used in the macOS build (we only mention it as a possibility in https://tailscale.com/kb/1207/small-tailscale/ https://tailscale.com/kb/1207/small-tailscale/, which is for embedded systems), so I have no done any benchmarking with it.