Yes, we recommend downloading the newest official version of Max2Play. You can choose between the stretch and buster version. However, if you have the Pi4, you need to download the buster version.
You can activate the premium license as always. Just enter your license (email address or code) in the Settings/Reboot menu and click save.
Yes, you can use Etcher to select the downloaded .img file and burn the image on your 32 gb SD card. Make sure the card is fast enough, though (Class 10 or higher).