Not sure what exactly is going on, but whenever Tracy is resolving symbols I'm seeing GJS code block in dlsym() hundreds of times per frame with the sort of backtrace like on the screenshot, leading to massive lag in some cases. Thankfully, TRACY_NO_SAMPLING=1 removes most of this interference.
I guess normally GJS hits some sort of cache for these hundreds of requests when it doesn't contend with Tracy? Either way, a bit unfortunate.