Newbie 3D Printer here, go easy

[Roberts_Clif]

It appears you are doing every thing in the correct order.

Leveling the bed is kind of an Art until you have more experience under your belt some may fail an some will work.
Some times you just have to learn from your experiences.

[Bikeracer2020]

Can only suggest that you try a bed leveling test somewhere along the lines of..
https://www.printables.com/model/171544-bed-leveling

I use something similar only with 13 squares. I don't know what bed plate you use, but if it's a flexible one you can always stick a piece of aluminium tape on the underside in any particularly low places, sometimes more than one thickness
Sometimes the bed is warped or bowed and that's the best way I've found of sorting it

Just look at each square and try and determine where the bed is low or high, if you're not sure set the 'Z' offset in the slicer by +0.02mm at a time and reprint it, that will then give you a better idea of which way to go.
Set layer height at 0.2mm, only one layer.

A bit tedious I know, but I have not checked my bed level now for several prints, I just wipe the PEI sheet in position and wipe with IPA and a paper towel before each print

https://www.toolstation.com/aluminium-foil-tape/p97723