So far, it is likely that the information present in the literature is not so helpful since there are different opinions in this regard. However, given that Cortinarius rubellus is extreamly toxic I would say (also based on the paper you posted) that also C. Gentilis could contain orellanin (probably at much lower level than in C. rubellus)
A screening of C. orellanus, C. rubellus, C. gentilis, C. cinnamomeus, C. malicorius, C. phoeniceus and C. sanguineus by a chemical test (https://www.researchgate.net/post/What_are_methods_to_identify_between_edible_and_non-edible_mushroom#546a6d68cf57d7c83e8b459b) showed only C. orellanus and C. rubellus to contain orellanine.
a finnish vet Eeva-Liisa Hintikka did a toxicological sudy on C. gentilis, and it is not at all toxic. This is not surprising, as the species belongs to subgenus Telamonia, and C. rubellus belongs to subgenus Cortinarius - they are only remotely related.
I was not able to find the actual study, but this is widely known by all Finnish mycologists.
Maybe you would like to ask it for yourself , and ask about the other species as well. As far as I know, limonius is not toxic, although it belongs to the same section than rubellus.
oh, and also - that original study was showed to be flawed, as the original material still existed, and it contained both species - gentilis and rubellus. So the toxin came from rubellus, not from gentilis. A good example why we need people who know their species ;)
A recent study interestingly found that Cortinarius armillatus contained low amounts of orellanin, less than 1% of the toxic species. Cortinarius armillatus have been considered as an edible species. https://www.researchgate.net/publication/295673249_A_novel_orellanine_containing_mushroom_Cortinarius_armillatus
Article A novel orellanine containing mushroom Cortinarius armillatus