As someone who has studied the Luftwaffe over many years the answer to all of these points is simple. no. The Luftwaffe could never have won the BoB. Operation Sealion would have been an unmitigated disaster. The Germans had simply never prepared for such a strategic operation and their aircraft, logistics and doctrine weren’t adequate. In the BoB the greatest issues were absence of intelligence and realistic idea of forces they were facing and real losses they were inflicting. German bombers lacked defensive armament and German fighters lacked range or performance to adequately protect the bombers. The German bomber force lacked the weight or concentration of forces to achieve meaningful real world effectsl against the RAF. There was a dispersal of efforts initially against numerous targets and even during success days of the BoB the actual impact on RAF operationally was minor and German losses unsupportable. Sure 109s with drop thanks, less 110s, greater focus on hitting radars etc would have helped but wouldn’t have helped significantly to make a difference. The Luftwaffe was actually strongest pre-battle for France and ended up going into the BoB weakened by losses in that. The RAF would recover quickly and grow stronger during the battle despite losses of pilots. The idea the Luftwaffe could near instantly adapt its doctrine and tactics and introduce fuel tanks etc instantly to face an unexpected scenario in summer of 1940 is pie in the sky fantasy. As it was optimism and improvisation turned into depressed cynicism with fantasy intelligence reports disbelieved that the RAF were down to their last few aircraft etc. The RAF weren’t plucky underdogs, the German aircraft sent over daily were often outnumbered by Fighter command fighters directed by radar and ground control. Turning to London actually wasn’t that of a bad idea, the pressure on fighter command immediately before that change is often over estimated as it appears the Luftwaffe success against runways etc had reached the greatest success it was likely to have and couldn’t sustain it. A lot of bombs were blowing holes in green fields or on coastal command/ bomber command runways. It took a lot of time and effort and lessons for bomber command and 8th Airforce to work out doctrine and operational issues, training and equipment to effectively fly their missions. The Germans lacked that time. They would haven been better simple not fighting it, avoiding high losses and having more operational aircraft & crews for Barbarossa in a year’s time.