all the advice given is good advise.
but there is 2 more thing to look at.
the X gantry has to be assembled and this is where you might have to check.
the 2 screws that secure it on either end will allow a small amount of movement if not secured well. (i had a similar issue) and might be moving slightly when the printer is printing.
the second is the runner wheels that the the X gantry rolls up and down on.
make sure that these are not over tightened against the tracks as this would cause too much drag and might be affecting you alignment / levelling issue.
my bed on my ender 3 v2 was also slightly bowed up in the centre of the bed (0.2mm) and i had to print in the middle for a while. however after a while (a week or so) my bed has settled (i think it was the heat cycles) and is now almost completely flat. it seems that the alloy bed, being press stamped, will never be perfect but should settle down. (unless its way off)
i level manually and don't have the BL touch.
i have not had to level my bed now for about 4 weeks and only check it if i have printing issues witch is zero at the moment.