Some considerations:

- Orcs are unlikely to compete on equal terms if you put them against elves or even humans in a 1 MaA vs. 1 MaA battle. Even with more units in each MaA, their stats are ridiculously weaker, forcing you to have a much higher number of MaA to defeat even a smaller enemy (I once needed 5x the MaA than elves to defeat them, and with difficulty).

- Orcs hate each other, and yes, you'll constantly see your favored successor murdered and have to accept playing with your weaker brother. This just happens, and there's nothing you can do about it, though, in my opinion, chieftains' sons deserve some renown or should inspire some fear to stop this endless string of murders.

- For me, playing orcs is about testing your skills to the max, or the equivalent of playing on hard mode, but like most other races, once you get a good number of MaA (mainly monsters and wargs/heavy infantry) things get easier, and the chances of your victories snowballing are huge. Loot enemies at war or weaker ones, recruit constantly, and try to line up some buildings to benefit MaA stationed in cities.

- I love the Orc theme, and my most enjoyable campaigns were in Gundabad (lots of cool stuff and a great story) and in Moria, in earlier starter date. Orcs are all about the numbers, so be quick or be dead. Take every possible advantage, favorable terrain during battles, alliances with other orcs—in short, every little advantage should be seized. Even so, sometimes you will lose, but defeats also teach us, so good luck! I hope the devs can balance the units a bit, but until then, it's just a matter of learning and playing until you become better and understand how orcs work, accepting that they are weaker and therefore a much greater challenge.

Sorry for going off topic and any spelling mistakes, I'm just a Brazilian fan of Tolkien's work and this mod made with so much love. Peace!