Reproduction steps:
1. Open the attached project “PerformanceIssue”
2. Open “Packages/CriticalForce.ObjectBuilderTool.Unity/Samples/Scenes/SampleScene” scene
3. Enter the Play mode

Expected result: The Editor enters the Play mode in a couple of seconds
Actual result: The Editor freezes for a minute or more before entering Play mode

Reproducible with: 2021.3.20f1, 2022.2.9f1, 2023.1.0b6, 2023.2.0a4
Couldn’t test with: 2020.3.45f1 - Errors in a custom package

Reproducible on: macOS 13.1 (Intel), Windows 10

Note: Removing flex-direction lines from .element--controls and .element--data in SampleStyle.uss removes the performance issues