ITER is a many stakeholders project, with all it's advantages (the costs can be split among participants, international cooperation) and disadvantages (each government wants a piece of the pie - components are manufactured at many subcontractors, in multiple countries) and politics (for example the multi-year process for selecting a ITER location).

The bigger, principal problem of ITER is the used magnet technology (niobium–tin, niobium–titanium). This was safe and conservative choice in 1990s, but as consequence the tokamak has to be big and therefor expensive to build.

Commonwealth Fusion Systems is currently building a tokamak based on the same physics as ITER, but with modern magnet technology using rare-earth barium copper oxide (REBCO) high-temperature superconductors. Their ARC tokamak should be smaller and cheaper than ITER.

https://en.wikipedia.org/wiki/ARC_fusion_reactor https://en.wikipedia.org/wiki/Commonwealth_Fusion_Systems

Of all the fusion energy startups Commonwealth Fusion Systems is nearest to demonstrating a realistic fusion power plant.