Arabs never really dominated over NW Africa

[Nassbean]

This is a common misconception when people think that arabs ruled over the maghreb for centuries if not millenias while the truth couldn't be farther from this. Reality is that the conquest of the Maghreb was actually the longest and hardest campaign(s) of muslim armies + those early armies incorporated freshly converted berbers from libya :

The energetic Uqba ibn nafi, who had distinguished himself in Syracuse, in Cyrenaica and perhaps even in Kawar, took in 669 the head of a reduced army, 10,000 Bedouin cavalrymen, it seems, but, significantly, reinforced by several thousand new converts from Cyrenaica.

Jean-Marie Lassère, Africa quasi Roma, p. 738

the same Uqba ibn Nafi got killed by a berber army under the command of Kusayla :

[...] in 670, and in 681 an army under 'Uqba ibn Nafi' marched across the whole of the region and arrived on the Atlantic coast; though they were ambushed by Berber tribes on their return and 'Uqba killed. It was these Berbers, rather than the residual Byzantine administration, that provided the principal resistance to the ensuing Arab conquest.

Roger Collins, Early medieval Spain, pp. 147


These arabs got expelled from the Maghreb 30 years only after their conquest :

Regardless of their martial ability, the Syrian junds failed miserably in quelling the uprising in North Africa in 741. As a result, the governor of al-Andalus eventually invited the desperate troops in Ceuta to cross the Mediterranean and enter al-Andalus in order to help him put down a similar Berber rebellion

Erich B. Anderson, Rise of the Berber mercenaries: Desert nomads come to Europe


Therefore what about all these so called "arab" dynasties ? Well it's now established that these were in fact berbers who claimed arab heritage especially sharifian lineages in order to legitimate their position :

More soundly based than Guichard's conclusions are the insightful observations of Glick. As he remarks, "arabization of the Berbers during this period must be carefully qualified", noting that "many Berbers falsified their genealogies, adopting Arab tribal names in order to dissemble their true ethnic identity." This is correct, and no less true of so-called "Arabs" than of Berbers in al-Andalus. Not only were they concerned with hiding their true origins, but also by claiming association with one of the elite tribes of early Islam, a definite social and religious status could be automatically achieved; all a part of the much-discussed "Arabiyya" (arabization) propaganda (tough too few authors have recognized this aspect of the problem). Furthermore, the early muslim chronicles of the conquests (not of al-Andalus, but in general) make it eminently clear that the true Arabs were opposed to travelling beyond the boundaries of their homeland, and had little interest in settling such far-away places as Iraq and Syria, much less Spain.

Jews, Visigoths and muslims in medieval Spain by Norman Roth, p. 47



Later during the XIth century, we see the famous Hilalian invasions : some turbulent arab tribes sent to the maghreb to punish the zirid vassal of Fatimid who decided to become independent .
These arabs again got defeated by almohads in Tunisia and were sent to Morocco and andalucia to serve as cannon fodder but it's undeniable that these tribes had an important socio-cultural impact in NA :

In 1161, the Beni Hilal, once again in revolt, were crushed near Kairouan in a battle against the army of the Almohad sultan Abd al-moumin. A thousand people from each Jochem tribe were then forced to provide contingents for the wars in Spain. The Beni Hilal were thus massively displaced towards the western coasts to be enrolled in the holy war in Andalusia, as were the successive sovereigns. [But it is especially after the battle of Gabes in 1187, fought by the Almohad sultan Yaaqoub al-Mansour against the Bedouins and their ally of the Almoravid clan Ali Ghania, that the Bedouin tribes were deported in large numbers to Morocco.

Mouna Hachim, Unexpected History of Morocco, p. 266