You can definitely export your data from Roam. Maybe not some types of data, such as images, but you can scrape that if you needed to. I can say this for certain as someone who's worked on open source import, export, and backup tools for roam. [1, 2]

[1] https://github.com/MatthieuBizien/roam-to-git

[2] https://github.com/adithyabsk/keep2roam