Ohrid matters to Slavic Christianity roughly as Iona matters to the Christianity of the British Isles: a small place where a literary and monastic tradition was consolidated and from which it spread.
Clement and Naum, pupils of Cyril and Methodius, arrived in the late ninth century after the Moravian mission collapsed, and the school they established taught in Slavonic, trained clergy and copied books. Old Church Slavonic in the form that became standard for Orthodox worship across the Balkans and later Russia owes a great deal to this work, and the alphabet now called Cyrillic was developed in this milieu rather than by Cyril himself. Ohrid became the seat of an archbishopric, and its lakeside churches carry frescoes and icons among the most studied in Byzantine art.
The status of that see is the long argument. It was autocephalous, then subordinate, then abolished by Constantinople in 1767, and the modern claim to inherit it produced one of the most protracted disputes in Orthodox Christianity. A Macedonian church declared itself independent in 1967 and was recognised by no one; the split ran for fifty five years, cutting a large population off from communion with the rest of Orthodoxy, and was settled only in 2022.
The dispute is a good illustration of how Orthodox jurisdiction works, since nothing in it turned on doctrine. It was entirely about who has authority to grant independence, and to whom.