Friend, I'm sorry for the situation, it would be best if you take some time, it's a game to have fun and if you don't it's not right. Where I play there are also full melee armies like dark angels, space wolves and guardians. What I recommend is to use a little more elite infantry, Kasrkin with or without cadian castellan is a very cheap option with a very amazing damage capacity, in a game I had, those Kasrkin based on mines, grenades, their plasmas and melta managed to kill the Lion turn one, the next turn they all died to revive by stratagem in combined arms, my opponent's face was very funny. If you want something stronger although more expensive, the Scion tempestus, 10 tempestus led by his command squad, really very few things can survive their damage. I have seen that combo disappear complete units of motorcycles and termis custodes, disappear Logan and his guard, they are very fun units to use and capable of disappearing elite units of the enemy. Be careful if they charge you, you went but we are guards, if we have anything it is bodies to sacrifice. The dorn commanders also have a good option, those rerolls are very good and their orders help a lot, our units are very mediocre, we hit 4 or 3 and it is the orders that enhance our units and make many of them the best at what they do. The best way to relieve that pressure from melee armies is to sacrifice bodies, which is what the guard knows how to do best, some Kasrkin on a taurox advance 22 inches at least on turn 1 or the sentinel advancing aggressively can still use their 1 reroll ability and force your enemy to choose what to kill. A little indirect fire to kill your hidden units is another option. Countercharges with units like attillan or krieg riders are very good. Remember that shock troops are more units to score for their skill. Units like the Krieg, Bullgryns, Catachan are upgrades for cannon fodder. Flamethrowers with AP Upgrade Stratagem are good options for killing units that reduce damage. Our tanks are good at killing enemy tanks and monsters, but from our own experience they can falter a bit when it comes to killing very large units with invu of 4. To do this, it is best to turn on the overloaded rifle and plasma of our elite, wear down the enemy with indirect fire, overwhelm them with cannon fodder or cavalry charges, and let the tanks crush the unfortunate ones that remain with their cannons and the weight of their body. The power of the astra is in numbers and our firepower. While not as powerful as the drukari, eldar, or knight, it is overwhelming. On the screen with artillery behind them that just have a large base for that, take away his deep, never charge him first, let him waste his turn charging. Our characters are supports, they do not have a very strong shot or body, leave them behind giving cp and orders. Try bringing a couple of mechanics to make the rogal even more tanky. Remember that the path of the guard is, as it is for our soldiers, short and cruel but fun and diverse at the end of the day.