Please see this post about general guidelines and suggestions for posting to this forum category and specifically how to correctly quote from input files, so that the forum software does not try to interpret special characters as markup. I’ve made the required change on your behalf this time. In the future, it will be better if you follow this yourself, since the chance to get meaningful help is correlated to how easy it is to read your post.
Fix indent provides access to the total force, not the maximum. That is a more meaningful value, anyway.
This cannot work. You cannot output scalar properties with a custom dump, only per-atom properties. Instead you must output those via a custom thermo style or fix print or dump styles yaml or netcdf (which require those properties to also be output as custom thermo output).