Hello Quentin
Thank you for reaching out to us. Let's see if I can address your concerns.
The partitions you see are needed by the operating system. Although it is possible to remove the recovery partition, it is not recommended. Doing so can impact your ability to refresh, reset and complete other repair options. They may even make it so Surface does not operate normally. Yes, it is possible to move the recovery partition to a USB device, but the results are not always optimal.
If you have concerns about storage, consider these options.
Best regards