The l4d2 workshop is honestly a dumpster fire when it comes to actually finding campaigns because it had 0 moderation and so people tagged items with every possible tag. If you’re coming back to l4d2 i would really recommend checking out some custom campaigns like Dead Before Dawn. Which is okay but I’ve never been a fan of their survival mode. The new survival maps as far as I can tell are additions to the original l4d1 maps that didn’t originally have as many.
The new campaign is fun, it’s two maps and it took me solo about 40 minutes to beat. The Counter Strike weapons have been in for a long time just not as polished and hidden, originally given to German players because they got a downgraded game.