Same way you plan to do it in your system, build a gossip network on top to share the scrapped data from the DHT or make a network of relays that forward things to the DHT but also gossip it with whoever wants to download it all ... or whatever.
There is nothing in using the DHT that makes using gossip in parallel impossible... the only thing makes gossip impractical is that it is inherently impractical.
Remember... Nostr already doesnt have gossip and actually started as a critique of gossip (Secure scuttlebutt), and Negentropy was invented on top.
Yet somehow you make it sound like Nostr relays are inherently gossip friendly, well, extend the same grace to Pkarr relays.
You get exactly what you want, but also a DHT to fall back to when your system inevitably fails for the vast majority of web needs.
Nostr relays aren't "gossip friendly", they just have a "latest" query. How do I ask the DHT for the latest updates?
Again, either scrap the dht as the BEP i linked to explains, or run Pkarr relays and add extra endpoint to get latest submitted stuff.
Also, what Nostr relays are you asking for latest updates? All of them?
DHT nodes organize themselves in a structural way so you can find them all if you try, so they should be simpler to scrape than Nostr relays, which you don't know them all.
Anyways, I think you are not suggesting a practical solution, and what you actually want is just an extra requirement that DHTs don't make harder at all.
