FIXED! I also have the issue with unreadable text in all the inflight menus including VFR maps and checklists, etc. Since the March update.
I have a three monitor setup in 2D. I use the surround display setup via Nvidia control panel. My resolution in MSFS 2D “PC” graphics settings defaults to 5760 x 1080. I solved the issue by dropping the resolution down to 1920 x 1080 in the “PC” graphics 2D section in the “General” menu,
Now the text on VFR maps etc.in VR are back to normal.
Hope this helps.