Currently, you only get a nondescript error and have to guess that this is the issue.
Making it work with gradle 8.7 would be nice, however I understand that development has moved on and MC1.20.1 is not supported anymore.
Therefore an alternative solution would be to at least release a new version of NG6 that fails fast with an explicit error message that states that it requires gradle 8.5 or earlier.
NeoGradle 6 does not support gradle past 8.5.
Currently, you only get a nondescript error and have to guess that this is the issue.
Making it work with gradle 8.7 would be nice, however I understand that development has moved on and MC1.20.1 is not supported anymore. Therefore an alternative solution would be to at least release a new version of NG6 that fails fast with an explicit error message that states that it requires gradle 8.5 or earlier.