Really happy with Projection Lab in this space. Although it's not open source, it is self-hostable if you pay for their lifetime access. The developer continues to update it, and has pretty much all the features I want for managing retirement projections.
As someone who has used it, would you say the lifetime option is worth $800? That seems really steep. It wouldn’t pay itself off over monthly for over 7 years.
It supported most UK scenarios but I felt like it never got personal taxes quite right. It seemed to be out by about 2-4%
But maybe I didn't fully understand it, partly because of the way it calculates it as a repayment in the following year (our income taxes are deducted at source and paid monthly)
