Draw the complete path
A download travels through the client, access point, router, internet connection and remote service. A fast label on one step cannot remove a restriction elsewhere. For a local transfer, storage and the other computer also belong on the diagram.
Use paired observations
Record the connection properties beside each test result. Note distance, power mode, whether the computer is on battery, and whether another transfer is running. Repeat enough times to see whether a change is consistent; a single unusually good run is weak evidence.
MLO benefits vary by client implementation. Treat a faster single-band result as an observation worth investigating rather than proof that the entire feature is broken.
Create a useful support case
Send the hardware model, driver and firmware versions, a short reproduction sequence, and the comparison you performed. State the user-visible problem in concrete terms, such as a local transfer pausing or a call dropping. A concise before-and-after record is more useful than an unfiltered collection of unrelated logs.