Interesting question actually and one removed from the tackiness of some on a previous thread.
Imho – no they do not dissolve into oblivion – they live on. And there is much evidence to suggest this is true.
The gods of the roman era for example were all incarnations of previous deitys and have continued to live on under a new moniker who are now known as “Christian” or “patron” saints. For example we had Dionysus who morphed into bachhus
Nimrod's (zeus) wife, semiramus (Babylon) has been re-incarnated down through the ages as Diana (roman), artimas Greek), even mary of the catholics. A small sampling but you get the idea
the cultures may be different but they keep the same gods. The body dies but the spirit lives on.