While the standard web version doesn't have a direct "Download" button for the whole hard drive, you can install it as a Progressive Web App (PWA) . According to YouTube , you can click the "Install" icon in the address bar to add it to your taskbar for easier access. Actual offline map downloading is primarily restricted to the mobile app Google Help .
Most modern PC map tools use a "Select Area" feature to download specific regions. Map Downloader for PC
This allows you to "put together" custom layers, points of interest, and routes. You can create a new map, name it, and add specific data points which can then be shared or exported Google Help . While the standard web version doesn't have a