Several other major CAs including DigiCert do DNSSEC validation but I haven't used them and so can't even tell you from my own experience how well they work, though it seems likely some of their other customers might have noticed on that end.
Now, are they all doing a "good job"? If you actually were paying any attention at all in this space you'd presumably have quoted my already published opinions about that. I think they should retain the DNS responses the same way they would keep the actual raw data from an HTTP validation. So third parties doing incident investigation can do an effective post mortem - I also think they use too many "short cuts" that are going to result in someone finding a nasty bug one of these days and for which there's no real evidence they're necessary.
But since it seems for you a "good job" is just using something operationally, then yeah, in that limited Thomas Ptacek sense of "good job" they're already doing a good job I guess.
(Obviously, just to point something out for the thread that you already know, the vast, overwhelming majority of LetsEncrypt issuances are for zones without DNSSEC signatures).
> I haven't used them and so can't even tell you from my own experience how well they work
... I'm not sure what my "confirmation" would tell you, beyond that I know how to read the paperwork from the CAs. But sure, both Sectigo and DigiCert say their systems should deny issuance on DNSSEC failure.