The Eastern and Western Empires put a combined invasion force together in 468 that met with disaster. Both empires knew that without N Africa the Western Roman Empire could not survive. The loss of the fleet (mostly paid for by the Eastern Roman Empire left it bankrupt), If you have Majorian win in 460 the invasion of 468 is butterflyed away so the eastern empire is spared the loss of their fleet, massive resources and loss of troops,
n 468, both the Western and Eastern empires attempted to conquer Africa again with the 'most ambitious campaign ever launched against the Vandal state'; primary sources suggest that the fleet numbered 1,113 ships and carried 100,000 men but this figure has been rejected by modern historiography, with Peter Heather suggesting 30,000 troops and 50,000 soldiers and sailors combined, based on 16,000 Roman soldiers conveyed on 500 ships in 532. Andy Merrills and Richard Miles have asserted that the operation was undoubtedly extensive and 'deserves admiration for its logistical brilliance'.
[22] At a
naval battle in
Cape Bon,
Tunisia, the Vandals destroyed the Western fleet and part of the Eastern through the use of
fire ships.
[14] Following up the attack, the Vandals tried to invade the
Peloponnese, but were driven back by the
Maniots at Kenipolis with heavy losses.
https://en.wikipedia.org/wiki/Vandal_Kingdom
As to the conquest of Gaul and Spain -- Majorian captured much of each but not both - and leaving large parts of the conquests as federate parts (ie Vistagoths)
"During his four-year reign Majorian reconquered most of Hispania and southern Gaul, meanwhile reducing the Visigoths, Burgundians and Suevi to federate status."
https://en.wikipedia.org/wiki/Majorian
