Zerotier UDP hole punching failed while Tailscale success

I Installed both Zerotier[v1.8.1] and Tailscale[v1.16.2] on my Ubuntu 18.04 server which behind an Enterprise firewall.
And I configured the firewall to allow 9993/UDP for Zerotier and allow 41641/UDP for Tailscale.

Now I’m testing if those two works by connecting from my Macbook, but things getting weird.
Screen Shot 2021-11-09 at 11.54.40
Tailscale always connect direct to my server instantly, meaning the UDP hole punching success right after just a click. But Zerotier “Relay” almost the whole time. During my 3 days testing, only one “Direct” connection was observed which disappeared right away and never back again after a switch to another network.

Please help to locate the problem and make Zerotier better.