Hello99,
I’m not sure where you get your parameters of levels 1 & 2. I have it differently, and I’ll provide sources.
I would there fore break down the levels as follows:
1) Things which although might enhance oneg Shabbos, are not essential. For these, not even a shvus d’shvus is permitted.
Some or all of these cases would be muttar according to the R’ma.