FYI: SketchUp installers have never automatically migrated extensions from previous installations. (This is a feature that many users have requested every year for many years.) You need to do it manually each year. There are utilities to do it in both Trimble’s Extension Manager and SketchUcation’s PluginStore, but you need to manually start the utilities by pressing a button.
FYI: On the CheckUp download page there are explanations of many errors and warnings.
Please Note this warning (from this page):
We gather data on your graphics card memory by querying Microsoft’s System Information. On some cards, what Microsoft reports is incorrect. This can cause Checkup to issue this error falsely! The presence of this incorrect result will not prevent SketchUp from running.
Obviously, since you have 16GB of VRAM, this warning is caused by sysinfo32.exe not being able to see the video memory amount. (I myself have a Nvidia GTX1060 w/ 6GB VRAM and sysinfo only reports that this adapter has 1MB, whilst it does report that the integrated Intel UHD 630 has 1GB of shared system RAM.)