1) Установка Flatpak
```
sudo apt update
sudo apt install flatpak -y
```
2) Добавь Flathub (источник приложений):
```
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
```
3) Установи PortProton
```
flatpak install flathub ru.linux_gaming.PortProton -y
```