How can one install games from a launcher like Ubisoft Connect into a separate drive?

So I recently switched from Win to Fedora, I really like the whole experience, but I can’t figure out how to install a game - Valhalla in this instance - into a separate SSD. I added the drive as ‘D’ in Wine configuration, I select the mounting point in the installer ‘Z:/mnt/bigssd/’ but the installer says there isn’t enough space. What am I doing wrong?

https://i.imgur.com/2pbNvHf.png

Should I look into symlinks maybe?

Try a web search for “ linux ubisoft connect”.
That seems to find hits for this issue.