There's no such thing as a standard benchmark, but I benchmarked 8 different setups using benchmark source from two competitor libraries. If you have a better idea let me know.
In the ideal you'd have to benchmark a heavy screen that you'd have to write for every competitor, and then provide timings across many different facets - initial load, runtime, total time, window resize, etc. As far as I know no one does that for anything, even backend stuff as it's just too much effort (even the TechEmpower benchmarks are micro and not like this).
If anything though Tamagui will look even better there. I've open sourced the results, re-used benchmarks from rival libraries, shown my work, and even published the 3 benchmarks that don't do as well for Tamagui. It's as Apples-to-Apples as it gets and it's not measuring anything weird this is straightforward stuff.