Depends on the situation on if bombing G is good or bad. If they are going tank dash then if you can drop them around 40 ipc or less than bombing is good as it is fewer tanks headed to moscow, if they are going turtle and making 40 though then its less effective.
Against this it is best to land UK troops in Karelia, lots of 'em, 6-8 a turn starting turn 2, along with heavy US landings in africa to choke Italy’s income. Also, be sure to hold Persia at all costs to keep the Japs from breaking threw, move the India forces back + TJ forces + 2-4 russians on R2. Do not abandon Kar on R2, esp if G bought 6 tanks. Build 2 inf there, stack everything in range there, and land the UK figs there if you must on turn 1. Keeping G from getting all 3 NOs without loosing stacks of units is a huge mistake when going KGF. On turn 2 let the british begin to stack it, along with taking norway/finland and/or SBRs, germany will never build 10 armor. Forget about the 1st Russian NO, its better for russia to loose 5 than to give G 7. Germany should only, if ever, get 3 NOs for 1 turn (2 or 3), and be down to 1 NO in mid game (4-5).
Then you want to either take Italy, or take and hold France or NWE. Do not trade France with more than 2 units and don’t prioritize trading france for a turn over dumping 8 units into Karelia if you cannot hold it! Do not take Italy if you cannot hold it. Do not build more defensive boats than you must. I see ally players get there fleets all out of wack by going for a quick Italy/France trade, or drop 6 units into france a turn to get destroyed a 2-4 G units and air, or build more boats than G has planes. These actions will cost you the war! At some point, around turn 4, you must make your move and do a large drop into France or NWE or Italy and hold the territory. Remember, NWE is worth the same as Karelia to Germany.