I've been struggling playing as Pyrrhus / Epirus. Do you have suggestions? What was your strategy?
Also, what is the fastest way to go through the first mission tree?
Rome starts an initial war with Samnium which you'll just miss out on, but which isn't a big deal. My plan was to be in Italy for the major war they tend to fight with lots of sourthern Italy around 453.
You only need "Settled Crown Disputes" to finish the tree, which you'll be able to select after the relevant Molossian event pops in May of 452. I selected "A Royal Wedding" immediately, and then spent the next two years going down the leftmost Corcyra branch to get them as a feudatory. You should be ready to hit "Settled Crown Disputes" sometime in 452, allowing you to finish the tree by early 453 at the latest.
I ended up building Heavy Infantry in my legion and using inventions to get army discipline but I think that was a mistake. You're simply not going to be able to stand up to Rome in a fight, and even sniping smaller armies is tricky in the small geographical area you're fighting in. I think you'd be better off saving your money and just building up your numbers with LI. One thing you do need is around 6 liburnians to transport your army efficiently.
You basically need to hit Italy in 453 after Rome gets involved in it's second big war. The Magna Graecia tree will give you a feudatory and an ally or two, so when you declare Rome can end up fighting almost everyone in Southern and mid Italy, if you get lucky. I also allied Syracuse, who didn't do much but YMMV. Honestly transporting your army is one of the trickier parts. There is a roving pirate fleet you have to dodge, and you shouldn't actually declare until you have your army in Italy, otherwise Rome will snipe it with their fleet. Land in a feudatory the Magna Graecia tree usually gives you in southern Italy. I think I used Tarentum.
At that point, everyone fighting Rome is just a distraction for them. I immediately snuck my army to Rome, assaulted the fort and then took Capua (the war goal), which let me almost fully annex them. I would then immediately integrate Roman culture and try to move your capital to Magna Graecia/Italia ASAP because your military and political situation is actually still fairly precarious.
Again, I only pulled it off on my 3rd try, so it is very RNG dependent. I'm also sure this can be optimized and improved on by better players. I'm very much a mid tier player. But it is definitely still possible to take down Rome early.