MiniJinja is now almost at compatibility with Jinja2. Latest release finally adds loop.previtem/loop.nextitem. Latest release is also fuzzed and hardened and has fuel support and stack overflow protection. https://github.com/mitsuhiko/minijinja/blob/main/CHANGELOG.md#0290
Might actually be fun at this point to try to expose it to Python via pyo3 and see how they compare.