It sounds to me like when you flashed your firmware to use Cura 2.6.69 your Z-offset got adjusted and was never put back to where it needed. The z-offset is the distance from the top of the leveling washer to the top of the PEI print surface and affects how tall your first layer is.
This can be done through the LCD menu by clicking the LCD knob in once to bring up the main menu then navigating to:
Configuration --> Advanced Settings --> Z-Offset
Then, you can make your first layer more squished by turning the knob counter-clockwise. You can make your first layer less squished by turning the knob clockwise.
Once you have found a good setting for the z-offset, make sure to back up a screen and Store Settings.
The typical z-offset is a number somewhere close to -1.35mm. If you change the z-offset from -1.35 mm to -1.45mm this will make your first layer more squished. If you change the z-offset from -1.35 to -1.25 this will make your first layer less squished.
Here is a photo chart of what a good first layer will look like based on squish.
When first testing this new offset, keep a careful eye on that first layer. If it appears the nozzle is being dug into the bed, turn off the printer and adjust the offset until it no longer does that.