The following page on netify.ai provides details on domains, platforms, networks and IPs used by TikTok.

The coygeek page provides detailed steps to add the list of TikTok resources to a custom block list.

Netgate has a forum post has some pretty good info about blocking Firefox DoH (DNS over HTTP). To me I would rather block DoH to decrease the attack surface.

pfSense

Block DNS over HTTPS nonsense. DoH (firefox uses DoH, so could still reach TikTok). See this Cloudflare page to learn more about DNS over HTTPS.

https://pfsense.local/pfblockerng/pfblockerng_category_edit.php?type=dnsbl&rowid=5

DNS Groups

https://pfsense.local/pfblockerng/pfblockerng_category.php?type=dnsbl

Going to tiktok.com will show it is now blocked.

tiktok blocked