Rating progress chart is confusing. Gridlines could make it better.

[Murilo-Perrone]

The image below shows my bullet rating peak. It was reached in April 2020, during the lockdown. However, the vertical bar makes it seem like this was accomplished in 2018. Ok, I know that the correct year is displayed in the tooltip box, but the year below is what really caches the user attention, because it is static (it is always there).

Proposal:

The solution I propose is to add some discrete vertical gridlines to the chart. The interval in which the guidelines show up should be calculated based on the time range that was selected:

if range <= 7 days, then interval = 1 day
else if range <= 31 days, then interval = 1 week   // (one gridline for every Monday)
else if range <= 12 months, then interval = 1 month
else if range <= 5 years, then interval = 1 year
else interval = 5 years

Also, it is useful to highlight the exact beginning and end dates of the selected range. For such, a date could be displayed at the top left corner and top right corners of the chart. The top left corner already has buttons for interval selection (1m, 3m, 6m, etc), so those buttons would have to be displaced. Maybe moving them to the center would be best. Today they seem too discrete (I haven't particularly noticed them until now).

Here is a very amateur draft I did, just to illustrate the proposed idea: