Ideal method to create a "grid data map'"

I am looking to create a map that looks like this:
(apologies for the quality)
where the UK is divided into a grid and each “grid” point is a different value within a range (1-10). The closest I’ve been able to get is this:

This is using Plotly Express to create a Scatter Mapbox. The issue is that the markers are circle, so there is overlap and whitespace, which makes this harder for the viewer to distinguish between colours.

I am looking to generate a map of discreet points, using data from the centroid of each point


If your dataset is large, you might consider feeding in the data as a set of tiles,