Firstly, whats your campaign difficulty? The mod is not balanced for the hard difficulties.

You need to understand you're sometimes going to lose battles or towns. The Samnites joined with Pyrrhus in reality. Hannibal managed to turn some towns in Italy too.

Spend your initial money on building upgrades to increase your income, and get as many trade agreements as you can. Fleece everyone willing to give you non-aggression pacts for as much money as you can as soon as you can, unless that faction you intend on fighting in the next 20 turns. Do not over-recruit, especially on the first turn.

What you need to do is focus yourself on getting two full stacks that are based around a core of Principes. Camilan era Hastati are very squishy, avoid fielding them in large numbers.
My typical "Consular Army" Consists of 2-3 Triarii 3-4 Hastati 2 units of javelins and 2 units of slingers/archers (foreign or factional) If I can afford cavalry I will get 2-3 units of that, but otherwise the rest is Principes and professional mercenaries.

I prefer sword/axe armed Celts or Sicilians in the Camilan Reform Era since Rome suffers from a lack of swords. The Sicilian Marines I find to be particularly reliable shock infantry, especially against spears or light-medium infantry. They'll be harder to ship to the North so don't worry about that, there's plenty of good Celtic mercs up there, but they'll be excellent troops in the South.

Draw their troops out into a field battle if you can. Your two armies each on their own should be capable of defending themselves against even twice their number or even more depending on the terrain. Once you've killed the field armies of either one, then assess your financial situation. If you can afford a third army do so. This army can consist of mostly Hastati and Principes. Secure one of the towns and leave the Consular Army there, march your 3rd army to the other front and finish that war.

Leave an army in Tarentum or Pyrrhus will take it back. With that done keep your eyes on Sicily. Don't let Carthage take the whole island, If they threaten Syracuse, try and ally them. And even if they don't accept still consider intervention, since the timing of which may coincidentally fall *after* Carthage takes the city. This phase you should be setting your eyes on Sardinia and Corsica. Conflict with Carthage at this point is inevitable. (But a conflict worth dragging out for as long as possible... A certain person might show up at a certain point in time.....)

Take Cisapline Gaul at your Peril and Leisure. Spain should be next historically. But if you want a nightmare that never ends, go ahead and take on Gaul/Germania.

A long term alliance with Sparta and/or Athens is quite wise. They're very reliable allies, and they'll kill rebels in your territory, freeing up your legions for conquest or defence from invasion.

I hope all this helps you get through your first 20-50 turns

I am having the same problem as OP here. I played DEI quite a bit roughly a year or so back and I don't remember it ever being this hard? My difficulty settings are normal/normal. I manage to fight off the Etruscans however, by the time I start to contain Epirus I get slammed from the north by one or more barbarian factions and by that time both my legions are exhausted.

Maybe it's just rust on my end but this seems way too hard of a start for a major faction like Rome.

I've played a few games using different strategies. The best strategy I've found is to strike the northern territories of Rome (northern Italy region) early. Don't let them build lots of units. Pull back the army from Cosentia to Beneventum and recruit units from Roma to transfer to that army. Epirus will usually march north towards you. You can set an ambush or attack them in the field. Avoid attacking their army while they are in Taras - wait for it to come out.

Once you have taken Taras, DO NOT attack them in Appolonia. Make peace with them. Ransom their troops to make it easier to make peace with them. The reason you make peace is because 1) you don't want to split your troops between regions when you can only field a few armies, and 2) Epirus will be an ally in the inevitable war with Carthage.

I found this strategy to be much easier than trying to hold territories in Greece, and Epirus will fight Carthage at sea for you while you build a fleet. Building a fleet is important to protect Sicily. Destroying entire armies at sea with your navy is quite funny.

Niroc you have to take on the barbarians to the north early. Don't allow them to build up. Next, wait for Massalia to attack Liguria and the Insurbes or whatever they're called. They will beat each other up and then you can strike when they're weak.

I tried this three times, and it just doesn't work. The Etruscans can be beat if you rush them with full recruitment on the way, but Epirus just steamrolls you before you can even turn around to face them. They'll have better troops than you. They'll have more troops than you. Their armies move faster than yours, to the point where they can snipe Beneventum or Cosentia from the sea. It's unfair to the point where it's just better to play something else.

Just git gud

no - u just very bad

i waited for them 2 attack and then instantly counter pushed epirus and the Etruscans. since this was the first time for me playing i was very carefull/ im stuck now tho by endless attacks and waiting for some military reforms. i took over epirus mainland and a province above but that made alot of countries angry at me. now turn 120 2 allies bc i liberated some towns and 9 factions im at war with .-.

weird, I didn't really have problems with it. i did lose beneventum AND cosentia to epirus i guess, but then i sailed over to appolonia and took it easily, and in a few turns i took back cosentia and beneventum and finally taras.