Title specifies wireless microcontroller (Specifically, two Raspberry Pi Pico 2W) because I believe this is what is causing the issue. Here's a video demonstrating: https://www.youtube.com/shorts/wS2WM2ZJLks
Essentially, the settings for Auto Max Lair's programs dictate that you must use a code even in local host mode, and the code entry happens so fast that a wireless controller will regularly drop inputs. In the example, I use the code 1111 1111, since a code consisting of one repeating number has a higher success rate than other codes (for instance, I've also used 1212 1212, but this often results in an incorrect code). Even with such a simple code, though, it sometimes fails to fill out the code fully or misses the + input, getting stuck on the code entry prompt. This happens with enough regularity that I frequently hit the "failed to start adventure 3 times in a row" error and have to manually restart the program.
Honestly, I think just having the option to perform slower, human-speed code entry would fix this problem. I get why the program enters the code so fast (autohosting for other players), but for my setup (two automatic switches, no human players, local communication only), I would rather have the consistency of slow code entry if it means less errors.