For some reason, Bambu Studio has nothing in its UI to adjust Z-Offset. Bambu Lab only recently started adding manual z-offset adjustment to firmware on some printers (changeable on the device's display), despite it being something that impacts all of their 3D printers.
Like Pressure Advance, Z-Offset must be set via G-Code for the printer.
On the Prepare tab, if you go to Printer settings -> Maching gcode -> Machine start G-code, scroll down near the bottom and look for these lines:
;===== for Textured PEI Plate , lower the nozzle as the nozzle was touching topmost of the texture when homing ==
;curr_bed_type={curr_bed_type}
{if curr_bed_type=="Textured PEI Plate"}
G29.1 Z{-0.02} ; for Textured PEI Plate
{endif}
You can replace that section with the below code, adjusted for each of the build plates selections (based on your specific test results for your setup).
;===== for Textured PEI Plate , lower the nozzle as the nozzle was touching topmost of the texture when homing ==
;curr_bed_type={curr_bed_type}
{if curr_bed_type=="Textured PEI Plate"}
G29.1 Z{-0.02} ; for Textured PEI Plate
{elsif curr_bed_type=="High Temp Plate"}
G29.1 Z{+0.00} ; for Glacier, for example
{elsif curr_bed_type=="Supertack Plate"}
G29.1 Z{-0.01} ; for Frostbite, for example
{elsif curr_bed_type=="Cool Plate"}
G29.1 Z{+0.01} ; for Geco, for example
{elsif curr_bed_type=="Engineering Plate"}
G29.1 Z{0.00} ; for example
{endif}
0.00 is default. Higher numbers ("+" sign) raise the nozzle, moving it further from the build plate (for less squish). Lower numbers ("-" sign) lower the nozzle, moving it closer to the build plate (for more squish).
You can print some single-layer test prints (such as these) to test your z-offset setting.