I believe that nextpnr has integrated both a simulated annealing placer and an analytical placer (based on this publication from 2019: https://arxiv.org/abs/1903.10407) (see here for the work the analytical placer is based on: https://ieeexplore.ieee.org/abstract/document/6339278). I think they are also working on electrostatic placement but I'm not sure what the current status of that is.

There is initial electrostatic placement support for iCE40 and ECP5 in upstream nextpnr at this point, since a few months. But there hasn't been a stable release just yet.