One key change in the short term is the Topics API. This is the replacement for 3rd-party cookies in Privacy Sandbox. Basically, it allows sites to query your browser directly about what topics you enjoy, and Chrome will respond with topics based on analysis of your browsing history to allow for targeted ads. If it seems strange that a new "privacy" feature is still serving up data about you for targeted ads -- it is. And in fact, a lot of the proposed changes potentially just give Google more sway to act as a middleman, which ultimately gives them more data.

Will your experience change immediately? Likely not, but as with many things in this space, it's about the dangers of the path and its longer term implications, specifically here about corporate controls and softening the definition of "privacy".

Here's a decent overview with more far more details.