I am successful in making wifi calls on other hotspots, even my jiofi dongle if that helps. Some issue with jiofiber setup. CC are clueless and dont even try to understand the issue.
Tried nslookup both URL's,Can you guys what IPs are these domains vowifi.jio.com and epdg.epc.mnc861.mcc405.pub.3gppnetwork.org resolving to in both the setups.
In windows you can do nslookup vowifi.jio.com. Or via Android App he.net - Network Tools - Apps on Google Play and under DNS section.
For wifi calling to work, they should ideally resolve to 18.104.22.168 or 22.214.171.124, if not try experimenting by changing DNS servers to 126.96.36.199 or 188.8.131.52 or 184.108.40.206 or any other internal jio dns servers
We need to single out the issue, is it with router/ is it with connection itself.
can you try below mentioned commands in your setup by changing a.b.c.d in commands to following ip's
nslookup epdg.epc.mnc861.mcc405.pub.3gppnetwork.org a.b.c.d
nslookup vowifi.jio.com a.b.c.d
Get the DNS in the WAN connection of your router let that ip be w.x.y.z.
nslookup epdg.epc.mnc861.mcc405.pub.3gppnetwork.org w.x.y.z
nslookup vowifi.jio.com w.x.y.z
Post the above results so that they might help in diagnosing the issue.
Also, try installing cloudflare warp in windows/android and see if the nslookup commands of vowifi.jio.com and other works fine.