This particular pearl clutch is even stupider than usual when it was already explicitly not apples to apples. For a time-dependent load you have the other 90% of the budget for the nuclear reactor to figure out storage.

If the marginal cost of the SMR is higher than the all-in cost of solar, then it is always optimal to build the PV array even if you already have surplus nuclear. So the much bigger portion of the SMR cost (the reactor and fixed O&M) has to justify itself just on the loads that solar cannot feed.

Of course this is not true everywhere yet (and this does not apply to more efficient large reactors), but the niche for SMRs is smaller than traditional reactors and shrinking.