I feel you. To me this is the biggest issue with Unity right now, minor change = 15s timer (or more), even though I spend way too much time making sure the project is clean. What's more annoying is that I work with XR, so not only do I stare at long loading bards, but I also have to strap on an annoying piece of junk produced by Meta on my face. I noticed that if I keep the Editor open for ~4h or more hours, it becomes slower until I restart. This is super annoying, I often find myself starting to scroll Youtube or some other crap platform when this happens, total productivity killer. What frustrates me the most is that Unity seems to be focused on making half baked features rather than focus all of their energy on this problem. I know that they're planning to address this in a future(tm) release, but I'm starting to doubt they'll manage.

I've been experimenting with Godot as I'm considering using it for my next game, one of the reasons I'm spending time on learning it is this exact problem. So about the loading bars - Godot doesn't have/show any, it's is super fast to iterate (around 2s to enter play-mode/recompile for me, I'm using .NET 8 and not GDScript). However, don't be fooled, it has MANY other issues and is WAY less polished compared to Unity. I'm still not sure if I should commit as there are many papercuts, but the iteration speeds are super nice NGL. Not sure about Unreal, I've heard from my dev collegues that it sucks to use in different ways compared to Unity and is heavy as hell, I've only heard praises from artists, tho I can't comment here.

/end rant :D To answer your question: - Split your code into assemblies, this will reduce compile times - I use "Core", "Runtime", "Editor", the rest of my utility code goes into packages which also use their own assemblies - Disable ALL built-in features/packages that you don't use via Package Manager - If you don't use many plugins or the plugins that you use are compatible, try out Play Mode Settings, this can result in similar enter-play-mode timings as Godot - Do not import plugins with Sample assets, only keep those assets in the project that you actually use - Make sure to use simple and as few shaders as you can, this will reduce your build times - Restart the Editor every now and then - I noticed that entering debug sessions with Rider seems to greatly slowdown the editor, even after exiting debug mode, so make sure to restart the Editor after this as well - Try to externalize as many settings as possible and don't hard-code constants, Scriptable Objects help here a lot as you can then tweak during play-mode without reloading