If you hadn't noticed, Festool/TANOS have started including lid guides in the front corners of all newer production M 337 and M 437 Systainer³s.
They look pretty much the same as this third-party 3D-printable version, except they're color matched:
Lid guide to prevent damage on Festool Systainer3 SYS3 M 337 and SYS3 M 437
They look pretty much the same as this third-party 3D-printable version, except they're color matched:
Lid guide to prevent damage on Festool Systainer3 SYS3 M 337 and SYS3 M 437