You'll need a massive POD or PODs that explains the increased capability of the Italian Army and the ability of the Italian industry to support it at the time in order to achieve this
The Italian Army had struggled vs the Ethiopians, Lost against the Greeks and in OTL at the time you are suggesting suffered one of the most one sided defeats in history when Wavell's relatively adhoc force of 30,000 men utterly and comprehensively defeated an army of 150,000 Italians and captured Cyrenaica in the process.
So there is a lot for you to change to bring about this victory
As for your question - once Italy had effectively blocked the central Med Empire shipping was already forced to go the long way around via the cape so little change there
The Suez itself? Well I suspect we would simply see a continuation of the see saw campaigns as before with the forces of the British Empire regrouping and counter attacking to reclaim the zone in 41 with the Italians suffering all the logistic issues they were sorely pressed to resolve in OTL
With the success I do not see Rommel and his Africa Korps being sent - certainly not then as Mussolini would want to keep the op all Italian (especially as he had lost face in Greece) - and those forces are instead sent to the Russian front (and sadly Rommel does not become the 'good German' and just another Eastern Front General)
For the British it would look like a disaster, Churchill may even be 'deposed', but keep in mind the forces and equipment lost trying to support the Greeks and subsequent Crete operation (which would not take place in this TL) as well as those men and equipment lost during Sonnenblume - Rommel's sudden and unexpected advance into Cyrenaica in early 41 - it was about 5 divisions worth of kit and a lot of manpower that was sorely needed that early in the war - now not lost in forlorn operations.