Discussed this with Tor on Discord, performance for validation runs from 2.1.13 to 3.0.1 took a huge hit with the integration/replacement of the validation backend to use the inspector/property drawing system. A validation run to scan the entire project went from less than 30 seconds to around 8:30-9 minutes average. This seems to be caused by a few things, but the principal issue is that some of the types used for inspector usage are not as optimized for validator usage as they could be, particularly for memory usage and creation of Unity types that incur a lot of garbage collection (scanning the entire project took up the majority of my free RAM out of 16 GB total). An example symptom of this is that AddComponent is called many times to add Unity components which I did not previously see when validating in 2.1.13.
Tor has an example profiler binary file to examine based on a capture of a smaller example; I’ve not included it here as an attachment since it’s near 2 GB in size, but it’s available for download from Google Drive here (https://drive.google.com/file/d/1FOHhfd7Ba4U18INwb3EnhHUGO8acsxh6/view?usp=sharing).
Profile Comparisons (non-deep profiles) for the same run
Deep Profile Example (using a smaller example sample, not scanning the entire project).