Blender’s official 3D Print Toolbox documentation describes checks for solidness, non-manifold edges, intersecting geometry, distorted faces, thin areas and overhangs. Those are useful tests when a model looks plausible on screen but produces surprising slicer paths.
The toolbox is not a substitute for Bambu Studio calibration. If the same geometry prints on the 0.4 mm nozzle and fails with the 0.6 mm nozzle, that points toward process settings or hardware rather than a mesh error. But verifying the model removes one variable from the diagnosis.
Use the toolbox on a copy and record which checks fail. Do not apply automatic mesh cleanup to the only copy of a carefully fitted part: repairs can change geometry. The payoff is a fast, free preflight for downloaded STLs and models assembled from multiple objects.
Run Check All on a duplicate STL that has printed badly; distinguish a geometry defect from the nozzle, flow and first-layer issues you have been troubleshooting.