30:26 said that since the time of Solomon there had been nothing like Hezekiah's feast in Jerusalem. Now 35:18 says there was no Passover like Josiah's since Samuel. How do these fit?

Here are the verses as the WEB has them. Of Hezekiah's feast: "So there was great joy in Jerusalem; for since the time of Solomon the son of David king of Israel there was nothing like this in Jerusalem" (30:26). Of Josiah's: "There was no Passover like that kept in Israel from the days of Samuel the prophet, nor did any of the kings of Israel keep such a Passover as Josiah kept—with the priests, the Levites, and all Judah and Israel who were present, and the inhabitants of Jerusalem" (35:18). 2 Kings tells Josiah's Passover in its own words: "Surely there was not kept such a Passover from the days of the judges who judged Israel, nor in all the days of the kings of Israel, nor of the kings of Judah" (2 Kings 23:22). 2 Chronicles doesn't compare its two feasts, and these notes set the verses side by side without reconciling them.