A reminder that the average consumer device doesn't actually validate DNSSEC in its default configuration: it relies on its recursive resolver to set a bit on the response saying "I validated DNSSEC, things are all good". In that configuration, DNSSEC gets you no protection against this.

One of the reasons a variety of providers have been pushing for DoH is because DoH fully closes the risk of ISP MITM without needing individual site operators to do anything. This is why you're seeing folks like Firefox and Chrome enable DoH by default.