well there are legit provincial and national products, just expensive and hard to identify. But its possible. I had so far 1 National H3 (the old non Neo) and one national Skyline TG3, sources were DHS theirself. So you can get those but they are around 80-100USD per sheet and really not worth it. Ive never had any national blue sponge rubber, Ive seen a legit one for 160USD and I would never spend this lol.
The Hurricane 3 Neo provincial is a very very common rubber in China, you get this rubber in a lot of shops which are all legit. Its about 35-50USD and worth the money, because its cheaper but better than Tenergy. But it is only H3N, the others are not available on the market, only exceptional like tabletennis11 which are the official european DHS supplier.
In terms of blue sponge youre right, I think only CNT really know the blue sponge rubbers unless you find one legit blue sponge and youre willing to play about 160-200USD. But the rubbers dont make you Ma Long, thats for sure. They play better than T05 because of more grip and when you boost them they get pretty fast but still these rubbers don't play by theirself.
I would agree with the rest, if youre boosting enough commercial is fine too. If you want to play them without boosting none of them works that good, if you boost just a little like 2 thin layers provincial is going to increase the quality for sure. But boosting destroys the rubbers so after a month they are pretty much done and if a sheet of provincial is worth it than for you go for it, the rubber is easy to get and the best rubber Ive ever played in my life.