There isn't a DLC Blocker in the offline install. That said, I've checked the gog.ini that installs with the game and can tell you the two overpowered DLCs are disabled by default.
just installed the game and looked into the gog.ini and read
and tried to disable other dlcs in that way, e.g.
but after the tutorial i still got spammed by all the dlcs. and according to the ig-phone bloodsucker is also available and marked. specops vehicles are also in the garage.
is there something else i have to do to exclude those dlcs?