MacOS Dual Boot Elementary OS 6 Impossible

**Describe the bug**
When installing via USB media, installer fails to select correct partition with default option, and option to proceed in custom installation remains grayed out. This seems to be because an error in gparted doesn't allow the options for boot, root, and swap to show up in the installer GUI.

**To Reproduce**
Steps to reproduce the behavior:
1. Reinstall MacOS Catalina on Macbook Pro Mid 2017 in a small enough partition for Elementary OS 6.
2. Power off, and relaunch with Elementary OS install media (from 5/9/21 for OS 6 beta)
3. Fill out language settings and get to installer.
4. Click "Custom (Advanced)
5. Notice that apart from the 3 buttons ("Modify Partitions...", "Back", "Erase and Install"), the only thing visible in the white GUI is the text "Select which partitions ...". I don't know for sure, but it seems like the rest of the GUI should have contents and not be blank. It seems like something needs to be clicked to make the "Erase and Install" button not grayed out.
6. Click "Modify Partitions..." to make sure setup is correct.
7. Receive 2 error messages from gparted. "Invalid argument during seek for read on /dev/nvme0n2" and "Invalid argument during seek for read on /dev/nvme0n2". I wonder if these have to do with the blank GUI.
8. Forming proper Boot, Swap, and Root partitions with adequate space don't seem to fix the GUI and allow the Erase and Install button to become available.

**Expected behavior**
I would expect the GUI to have clickable partitions for installation, but it does not.

**Desktop (please complete the following information):**
- MacOS Catalina & Elementary OS 6 Beta 5/9/21

**Additional context**
I am happy to do more tests with any pointers you think of / updates to the software in case you don't have the hardware or time!