The U.2 form factor is a 2.5" drive, not larger than it.

"U.2" does not change anything in the mechanical characteristics of a 2.5" drive, it just replaces the SATA or SAS electrical interface with a NVMe electrical interface.

You can mount a U.2 drive in any location intended for 2.5" drives, as long as its height can fit there.

However, 2.5" drives come in various heights. Many laptops and mini-PCs that accept 2.5" drives accept only some of the smaller heights and they do not accept the greater heights, like 15 mm, which are typical for enterprise SSDs and HDDs, regardless whether they have a NVMe, i.e. U.2, or a SAS interface or a SATA interface.

This new high-capacity U.2 SSD has the standard 15 mm height of the 2.5" form factor.