for example: prize allocation for a campaign (signature) is around 2,000,000 tokens and if the project only has 1 participant in the campaign (signature) and when the project has been completed or not scammed, is it true that the participant will get the sum of all tokens (signatures)?
or maybe not at all, for other reasons?
No way that's not true or even going to happen since before the campaign was started they already arrange that if the cap for the participants was not reached automatically reduce the pool, that's the common practice or in the other they just cancel that campaign for the reason of lacking of participants.