Difficulties detecting long-thin objects

Thank you so much for your contributions.

I'm trying to train model to detect architectural objects and none of the models i train seems to detect long and thin object (as illustrated in the attached image).

• the dataset size is more than fair, it works fine on axis aligned object detection.
• Checked and manually retraced the annotation polygons and there no issue with that

Already tried the following architectures :

• Oriented RCNN (ResNet 18 with full sized images, R(50, 101, 152 )with the splitting pre-processing and ResNeXt101)
• Rotated Faster RCNN (ResNet(50..152) and ResNeXt)
• Retinatnet (ResNet101)
• ROI Trans (R50 and R101)
• ReDet with R50

and none of these exceeded 0.4 mAP for that specific class.

Do you have any architecture recommendation or a change in the config i can do to improve my results?