Personally I think the debut category should be eligible for anything that has debutted. Even if it's debutting as early access, that is still it's debut, and it still made an impression. If an unfinished game is beating out the finished ones in other categories though that sounds like its more a concern for those making the (increasingly lower quality) finished games. Pretty much every big name publisher has ran their own names through the mud at some point in the last decade, it does not surprise me when unfinished early access titles actually steal the bigger boys thunder at this point. Least I only paid $20-$30 for the unfinished indie title that probably has the same amount of bugs and playtime (or in valheims case, less bugs actually. Valheim is one of the mos stable early access titles I have played, more stable than some of the complete AAA games i own).

TL:DR if the unfinished game actually earns those awards over the completed games, maybe it's a reflection of the completed games lack of quality overall, steam awards are by popular vote after all.