Steps to reproduce:
1. Create a new Project
2. Create about 40 GameObjects in the Hierarchy
3. Enter Play Mode
4. Enable Stats
5. Start hovering over the GameObjects with your mouse in the Hierarchy
6. Observe the Statistics panel

Expected result: Performance drops are minor
Actual results: Major performance drops even when nothing is being rendered in the scene (300 FPS -> 200 FPS)

Reproducible with: 2023.1.0a1, 6000.0.60f1 (61dfb374e36f), 6000.2.8f1 (c9992ac36c34), 6000.3.0b6 (211490bb75a6), 6000.4.0a3

Reproducible on: Windows 11 Pro (24H2)
Not reproducible on: No other environments tested

Notes:
- While it is expected to lose some FPS while moving mouse or highlighting GameObjects, the Hierarchy takes the biggest toll on performance out of any window, on heavy projects the Editor could become unusable in Play Mode
- Similar results with Hierarchy v2