IPv6 won't work on macOS, Linux(Android) over Wi-Fi

Hi there! I'm using the latest OpenWRT firmware (19.07 series) on an x86-64 device as the router (gateway&dchp) for my home network (while having my main switch as my wireless AP and LAN switch). And here's the problem:

I have IPv6 connection in OpenWRT status and my Windows PC (connected via ethernet cable) works fine with IPv6 (https://test-ipv6.com & https://ipv6-test.com all return good results with IPv6 as default protocol and in Chrome DevTools, I can connect to websites with both IPv4&v6 using IPv6).

However, on my MacBook Pro (macOS Big Sur Ver 11.4) it's nothing like that. I can get the IPv6 address in the network preferences, and I can ping6 ipv6 hosts as well. BUT, when I try to visit a website (HTTPS, it seems pretty hard to find a non-https site using ipv6, so haven't tested that yet.) it simply won't open and will time out after maybe 0.5min (in chrome DevTools). And when I curl in the terminal , for example , curl -sv https://ipv6.example.site/ -6, it shows SSL_ERROR_SYSCALL, just like the issue referenced at StackOverflow. It also mentioned that the problem occurs only with macOS.

But in my case, if I'm connected directly to the modem (The modem is just the main switch I had used and it can also function as a switch, a modem, and a router) via wifi, I can visit IPv6 sites normally. So I guess it's a problem with my OpenWRT configurations.

On Android devices, the webpages from IPv6 hosts simply won't load and I haven't yet further investigated that.

Now there are two assumptions:
One is that it is a problem with lan&wifi difference and the other is a problem with TLS and macOS(as well as UNIX-based android).

But I think both of the issues should be solved within OpenWRT. Anyone has had the same issues like mine and is there a plausible answer to that?

Thanks a lot in advance!

PS: When my PC is connected via a USB Wifi dongle to the same AP as my mobile and MBP, it can also connect to the IPv6 network and visit Ipv6 Https sites but may drop access some times (I think it is some problem with the USB wifi dongle as it is pretty old and works on 2.4Ghz)