Excel - Highlight cell which is closer and smaller to a specific value

I would like to highlight a cell which is the closest the a specific value but still lower (below) or equal according to a formula.

For instance, if I have 14 in B4, I would like the cell 13 (or 14) highlighted but not 15 in the range.

The value I need to look for would be in B4 and the range that I must apply the highlight formula to would be L1:L371.

So far, the best result I was able to achieve was with (from what I was able to find using Google or Stackoverflow already existing content):

=SMALL($L1:$L317,COUNTIF($L1:$L371,"<="&$B$4))

Although, not only it selects the value I am looking for, it also selects all the values below.

May someone provide me some help so I can achieve the expected result please?

Thank you for your time and help, it is greatly appreciated.