Is there a way to disable IPv6 on the iPhone?

Before some of the overthinkers ask, why would you want to do that? I'll explain that my ISP is having issues with IPv6 and (one) of those internet evils called captchas.

Over the last few months something has changed with captchas which fail despite getting them right. I've tested this out over fifty times and I have no issue with the successful completion of captchas when using a VPN withOUT IPv6 or if I disable IPv6 on my PC. However, m OEM ISP provided XB6 router has disabled functionality regarding IPv6. It can only be disabled by manually doing so on the actual device like tablet, phone, or PC (if capable).

The other option is to buy a third party router and bridge the modem to obtain manual configuration for IPv6.