I understand your frustrations since you are forced to work within a codebase that is shared with other developers with varying levels of experience. Lua was from the get-go never supposed to be a standalone language, it is more of a complimentary language and if you fail to respect that then it becomes unwieldy, quick. It is extremely easy to shoot yourself in the foot with the language and once bad design decisions creep in it is hurts a LOT. However once you get enough experience with the language you manage stay within the "happy path" (which is EXTREMELY difficult when you are on a team with salaried software engineers with different and often misaligned incentives) it is actually one of the best languages available.

One of the things I suspect your team is doing wrong is you are using the PUC Lua C API instead of the LuaJIT FFI. That is one of those things which just completely destroys the "happy path". The PUC Lua C api is effectively a deprecated feature at this point. A few years ago you could have made the argument that the PUC Lua C API is more portable than LuaJIT which is absolutely true. But q66's (from Chimera Linux fame) cffi-lua project nullifies that argument since you can now use the luajit-style FFI in PUC Lua, which works on every platform that libffi supports.

Again I understand your frustrations with the language since you are working within a fundamentally adversarial environment. Perverse incentives can easily destroy any good patterns you can establish since the language is so flexible. I implore you to explore the language outside of your day job.