I have this timeline made using Excel and I was wondering if there is an easy to transfer this into Overleaf -
Excel2Latex may work for you,
but I was unable to get it working in my copy of Excel on the Mac (I have Office 365 and version 16.49 of Excel). It hasn't been updated in four years so you may have better luck with an older version of Excel.
The documentation is a little outdated. The options aren't in the Tools menu but, at least on my Mac, it's in the ribbon under Add-ins. The interface gets a little confused with my retina mac display (it seems to want to render things really small), but it does appear to work. By default, it assumes the
booktabs package is loaded but this can be configured.