gimp – Fix text anti-aliased by MS Paint

I’m trying to update a chart which has an 8-bit style but was imported to ms paint at some point. I like the overall layout of what’s there so far, but a lot of the text got anti-aliased:

I have the original text for some but not all of the chart, as there is an even older version which did not get anti-aliased:

Is there a tool that I can use to correct the text of the chart, bringing it back in line with the original 8-bit style? I would like to continue from the second chart.

If possible, I would like to use gimp since that’s what I already have installed, but I’m not particularly experienced with any image editing program so if you want me to install something different that’s fine.