I just took a quick glance at your thread, looks like the issues are related. I will take a through look at your thread later tonight. I also reformatted the SSD yesterday of the same box and installed PopOS (a ubuntu derivate) and installed bitcoin-core (flatpak). It is syncing way fast so far, and is at 77% in less than 24h. I kept the debug.log from the bitcoin on start9 and will save the debug.log of the bitcoin-core on PopOS and will then try to analyse the block validation timings.