Some of my domains get DNS-hijacked by my ISP's security filter - how do I check if this is happening on other ISPs too?

Found out one of my domains was being silently redirected to a sinkhole IP by my ISP - it's DNS-level filtering, flagging the domain itself.

Don't know exactly why it's being flagged. This is for solar panels, not even some grey vertical.

Only noticed because it broke on my own network, and switching to DNS-over-TLS bypassed it completely.

I actually also noticed this when just spying on ads on my burner phone how like the page wouldn't load for some other people running some other offers because of the ISP blocking.

Is this ISP DNS Hijacking becoming more prevalent?

Since I don't control what other ISPs are doing, do you guys have a good tool for testing whether domains are flagged/hijacked across other ISPs?

Also any tips on how to further not end up on these blacklists? Because I have more aggressive stuff that's not even flagged, maybe it is some specific trigger or