Ok so first off..
When you report a blatant cheater, You usually would do via Origin as described in this guide : How to Report Cheating in Battlefield 1
When you get to actually typing out what was happening, when, what game etc..
In the above box, You’ll see “Additional Comments”
So if for example, You had a screenshot of somebody cheating, Or a video.. You would upload your image to imgur ( or flickr ), Right click the image itself and then click “copy image address” which would give you a direct link to the image file.
Paste that link into the “Additional Comments” box.
Same goes for any video you have, Upload it to youtube and then once its processed and can be viewed at full quality, Paste the link into the box.
Balancing has been an issue for some time, I agree.
There has been lots of reports of performance issues, This has been confirmed to be included in the next patch.