According to Meyaoi, "Game estimated release date: Q4 2021 (might be postponed further if more route goals are reached)".
So, it was originally slated for 2 years until release, but we've already added about 4 extra routes since that estimate and we could still add a couple more, depending on how much we can raise by March 31.
In short, I don't think we'll have a proper release date estimate from Meyaoi until the crowdfunding campaign is finished, but at this point I'd probably guess it's around 3 to 3.5 years away ^_^ (but that's just MY estimate, we'll have to wait and see for a more accurate one)