I finally got around to building stellarsolver with the latest git. Looking good but maybe not quite as fast as astap, almost certainly because I've not yet worked out optimal settings. This is with default everything.
This coincided with a meridian flip at around 03:21:
[2020-11-20T03:21:06.375 CET DEBG ][ org.kde.kstars.ekos.mount] - Meridian flip planned with LST= "06h 17m 25s" scope RA= "06h 15m 09s" ha= 0.0379024 , meridian diff= 0.02 , hrstoFlip= -0.0179024 , flipDelayHrs= 0 , "Pier Side: West (pointing East)"
I intervened manually to reset the mount model to force a re-calculation, whereupon it converged.
Please let me know if these's anything I can do to help.