How to select Cloudflare as the sole Private Relay provider on Apple devices?

Hello, since the introduction of Private Relay, it is enabled on all my Apple devices, but I have noticed some inconsistencies - differences between providers.

When Cloudflare is enabled, everything is perfect, but when Akamai and one other provider (don't remember the name) are enabled it's not so rosy. The DNS servers of these providers accept bad, expired and missing signatures. RPKI v4 and v6 are also not available. Last but not least, both providers do not reach the speeds of Cloudflare.

My question to Apple is if and how it would be possible to choose Cloudflare and a single private relay provider?

Thank you.

Tools:

1) https://www.dnscheck.tools

2) https://cmdns.dev.dns-oarc.net

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