Iirc they working on it, they basically have inflatable pontoons or something like that that they put beneath the foundation of each building and raise them up, then drive new pylon/post supports into the bedrock. They were working on that when I was there in 2018, and as far as I know that's still the game plan. Essentially they have to raise the entire city above the projected increasing high tide line.

We should have the technology to reinforce the supports and raise Venice, but it would be really really expensive. Maybe the fee is also there to pay for those efforts as well.