I used to feel frustrated as a skilled gunner chopped off my wing at 1.5K, until I learned that it's all about patience. Like attacking GVs, you have to give yourself some time, climb above them and wait for the perfect moment to strike. Wait for them to be over the target dropping their bombs, or turning.
If you still want to creep up their six (and risk a quick death), at least take something like a Me-410 with the BK5 or MK103, aim carefully and you can score hits well outside of their defensive fire. But be careful, a skilled bomber will cut the throttle and open the bomb bays to close the gap and put you right in his sights!
Another way to learn a lot about attack approaches is, well...getting shot down
. I have probably learned more while getting blasted by Lusche and Bruv than attacking bombers myself.
Is it realistic to have bombers flying at full throttle all the time? No. Is the laser-aim historically accurate? No. But then again, this is a simulation, and there were some compromises to make it playable and balanced.