Is the cable length exactly 3 m for this listing?

Yes. UACC-DAC-SFP28-3M identifies the 3 m variant. A shared family photograph does not itself prove length; the part number determines the ordered length.

Do I need separate optical modules?

No optical modules are required for a supported DAC link. The copper cable already includes the direct-attach ends.

Ubiquiti lists 25, 10 and 1 Gbps for the family. Both endpoints and their configuration must support the requested mode.

Can it plug into a 100G QSFP28 port?

Not directly. This cable has SFP28 connectors, not QSFP28. Do not infer compatibility from the shared number 28.

What bend space should I allow?

The manufacturer lists a minimum 31 mm bend radius for the 3 m variant. Leave additional space for the connector bodies and strain relief.

When is dispatch expected?

Dispatch in 2-4 business days applies after cleared payment while stock is available. This is a dispatch estimate, not the arrival time. Delivery transit depends on destination and service; availability is rechecked before order handling.