unity
Unity
Ship on the default stack below. Each row names the one tool to reach for, so the choice is already made — spend the thinking on the feature instead.
Baseline: Unity 7.0 (7000.0, in alpha). It continues the Unity 6 architecture on CoreCLR: the Editor and desktop players run on CoreCLR, every other platform on IL2CPP. Code targets C# 9 and .NET Standard 2.1 until Unity ships .NET 10 and C# 14 within the 7.0 cycle; runtime.md owns what the runtime changes for your code.
7.0 aims at parity with 6.7 LTS and is not itself an LTS: the next LTS stream starts towards the end of 2027, so a project that must ship on long-term support stays on 6.7 LTS.
For what a 7.0 build actually ships, read its release notes and Unity's Discussions posts: the 7000.0 manual still carries pages written for 6.7.