From looking at the video, the problem is that the user doesn't see the package dependencies that are installed at the same time. The packages that are the problems in the video have a dependency on Burst. Burst is a big package to optimize code and take a lot of memory. (In the project settings there is an option to see dependencies, it helps to understand any problems. Also the dependencies are now always visible in Unity 22LTS+ in a Dependencies tab for each packages.)
Also on the end of the video we see a project with a simple scene that takes 3.5G of memory. Unfortunately the Packages folder in the project browser is collapsed and we can't see all the packages installed. My guess is (because I can see URP is used) that there are a lot of packages installed in that project. To fix that issue, the user should uninstall unnecessary packages in the package manager in the 'In project' view. Unity can't load only packages affecting the current scene as it's not possible to evaluate what to load from packages, so we need to load all packages while the project is opened.