Can small Clarity battery last long if driving EV mode all the time?

All well and good, but that does not satisfy the requirements needed for the battery to qualify for the Tax Credit.
The vehicle must be assembled in North America, but the battery is not under the same requirements - it is all about where the minerals and other components are sourced. It is widely believed that no manufacturer will be able to trace and document the source and value of everything in the battery for some time.
Mineral suppliers will have to keep track of - and keep separate - minerals produced in different areas.
Lithium can't come from the biggest suppliers worldwide, and there is no cobalt mine in a free trade country. If your battery pack has any microchips, they can't come from China, etc. This is a very high bar for manufacturers to achieve and most are saying 2-3 years before they can hope to regain at least part of the Tax Credit (it is awarded in two $3,750 portions).