You understand what the Panama Canal means to the US strategically, right?

Yes.

And who is putting lots of resources into it right now, yes?

Yes, we do. You apparently don’t. The improvements in the canal are being paid by Panama, out of the tolls collected by users of the canal. The US is not involved, except as a customer.

From Google:
No, the United States is not rebuilding the Panama Canal, but the Panama Canal Authority (ACP) is making improvements to the canal's transit management system. The ACP is also managing the canal's operations, administration, and maintenance

On the off chance you think this is another heroic American project, here is a list of the companies involved in the construction of the new, larger locks:

The engineering companies that worked on the Panama Canal expansion include:

Grupo Unidos por el Canal (GUPC): An international consortium led by Sacyr of Spain, which also included Impregilo of Italy, Jan de Nul of Belgium, and CUSA of Panama. GUPC was responsible for designing and building the new locks.

Simem S.p.A: Supplied plants for the production of concrete for the new locks and water recycling basins.

Cimolai: Fabricated the 16 gates for the new locks in Italy
.
Hyundai Samho Heavy Industries: Fabricated 158 valves, 84 bulkheads, and 328 trash racks for the new locks in South Korea.

Eaton: Provided power management solutions and products for the expansion, including arc-resistant medium voltage switchgear, pad-mounted transformers, and FlashGard motor control centers.

WSP: Facilitated the Panama Canal expansion project.