Offline installers are preferred by developers for several reasons:
Click the link to download. File sizes are large (~2-3 GB), so this may take time depending on your connection. download qt 5.15.2 offline installer
If the official server is slow, trusted mirrors include: Offline installers are preferred by developers for several
https://download.qt.io/archive/qt/5.15/5.15.2/qt-opensource-linux-x64-5.15.2.run download qt 5.15.2 offline installer
Here is exactly how to download the offline installer without using the online maintenance tool.
A community-driven tool that downloads binary packages directly from the Qt servers, bypassing the need for an online installer and Qt Account.