Warning: the TikTok WooCommerce plugin is harmful to your site... and TikTok support knows it
I was attempting to diagnose some slow page load times on my WooCommerce site, so I profiled a flame graph in DataDog of my PHP backend. Here, you can see the TikTok plugin making multiple outbound requests to the TikTok servers. Overall, the TikTok plugin blocked the PHP execution for roughly 300ms (this is on a high-end server, too; it runs about much faster than my virtual/shared servers). Even here, 300ms is enough that the TikTok plugin alone will earn me punishment from Google's page speed.
I ended up removing the plugin and installing a 3rd party pixel tracker plugin, which does the same job without the "phone home." Which begs the question: why is the "Tt4b_Pixel" code phoning home in the first place? Pixels should be front-end code AFAIK, not back-end.
FWIW, I told TikTok ads support about this. They spent the first couple messages trying to convince me that my Javascript speed was fine (lol). Finally once I explained what "sever-side code" was to them, they admitted that the team knew about the issue
I would say that their characterization of the problem significantly downplays the issue.