Ubuntu 20.04 LTS has Qt 5.15.2 in its official repos:
https://download.qt.io/archive/qt/5.15/5.15.2/qt-opensource-windows-x86-5.15.2.exe Note: The same filename contains both MinGW and MSVC options during installation. qt5.15 download
https://download.qt.io/archive/qt/5.15/5.15.2/qt-opensource-windows-x86-5.15.2.exe Ubuntu 20