[mhils]

I wouldn't write it off - one possible trick here is to also MITM the DoH/DoQ server and disable ECH by removing the relevant records from the DNS response. We've just added DNS support to mitmproxy and this is a natural follow-up. :)

[pdimitar]

Oh? Do you guys have a blog writeup? I would LOVE to read more about this! I want to eliminate the small amount of ads that make it through my PiHole.

[mhils]

Not yet, but you might be lucky soon. We have an RSS feed on mitmproxy.org and a Twitter account. :-)