Arguably the BotA ends sooner, because the Germans remain restricted in where they can engage in the Atlantic and escort resource concentration on British convoys, plus no wide open American hunting waters in early 1942, means the Uboats effectively cannot engage convoys effectively by 1942 on the North Atlantic route. Britain by itself cannot invade Vichy North Africa without provoking war with the French, so it is highly unlikely that they even bother. Instead Monty gets resources, but Rommel gets reinforced against and saved from total defeat once again, so fighting in Libya continues into 1943 and Italy avoids invasion. The Mediterranean stays closed. Malta probably doesn't because the threat of OTL 1943 due to lack of US air and naval forces to supplement it and the lack of a Algerian front. Plus also perhaps no 'land link' with nearby Libyan territory to Malta to strengthen it and allow Force K to operate from it again.
Without the US strategic air war from August 1942 and on the Luftwaffe can focus more fighters in Russia, which is a big problem for the Soviets, while they can also invest more in night fighters to shut down the RAF. The Axis have a lot more resources going into 1943 without the US help in the Mediterranean leading to the disaster in Tunisia both on land and in the air. Italy stays in the war on the Axis side and remains uninvaded for a lot time if not entirely during the war, which is a huge help for the Germans, as they lost a lot of manpower replacing Italian forces all around the Mediterranean when they defected...and when they kept suffering disasters in Italy.
In the East this may well not prevent Stalingrad and the resulting German retreat in late 1942...but given no US in the war, one of the most important reasons for the campaign in the Caucasus is gone. Case Blue as it understand it may well not happen and if it does it probably stays in it's phased form, which prevents OTL encirclement. So a lot of butterflies there potentially. Assuming that there is functionally no change in how the East plays out in 1942-early 1943 then by Summer 1943 the Germans have a ton more resources to use in the East than IOTL due to no major disasters in the Mediterranean (other than the retreat from Egypt) and the continuing see-saw action there. Italy pulls out resources from the East, but can really now focus on the situation in Libya better thanks to no Eastern commitments. Kursk ITTL is an even bigger mess due to the Germans not needing to retreat and having significantly more resources to throw at the Soviets. Ukraine may well not be liberated in 1943 even if the Soviets are advancing in Belarus. If that happens the Soviets run into a serious manpower crunch come 1944 due to lacking the 4 million men they conscripted in Ukraine and other liberated territories in the 2nd half of 1943-1944. Weaker Soviets, plus more German manpower and material due to no US entry then really hurts the Soviet ability to advance potentially turning the Eastern Front into a stalemate in 1943-44 and opens the chance of a negotiated peace deal.
Britain lacks the ability to do much even with expanded LL due to manpower constraints and the situation potentially in Asia (not to mention the Indian nationalist movement) with all the butterflies that entails. Butterflies get pretty huge which makes it pretty hard to say for sure, but without active US help and potentially a neutral Japan (or at least one that didn't attack the US and drag them into the war) it is hard to see the British and Soviets alone defeating the European Axis powers. Stalemate is the most likely outcome IMHO and a deal in 1944 based on exhaustion.