Assisted manual levelling with Marlin
Photo Credit: Courtesy of 3DStockPhoto ( image)

Write a few pieces of gcode to do this. Place it on an SD-card (I assume you have a reader) and select the file you want to execute.

Home all:

G28
G1 Z0

Do you really want to home it directly? I would say you want to take it down slowly and adjusting end-stops incrementally.

First:

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G1 Z10

Then

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G1 Z3

Then

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G1 Z1

etc etc

You can also move it around in the X and Y plane:

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G1 Z5 X50 Y30