the unity engine just takes a long time to launch m 2D CORE project.
What you should do: Provide more details.
other options to think about (while waiting for more info)
- use profiler argument to profile editor startup details Unity - Manual: Profiler window reference
- disable antivirus/defender for that unity version and or the project folder
- get faster ssd/nvme drive
- get more memory (if you are running low, virtual memory might be kicking in…)
2025: Can also try this, GitHub - needle-tools/compilation-visualizer: Unity Tool showing a timeline of assembly compilation. This is especially helpful when trying to optimize compile times and dependencies between assemblies. Besides showing a graphical view of compilation, selecting an assembly shows both dependencies and dependents of that assembly.
to get some idea about import and compilation times.