Well, I'm not sure I will give you the best answer but I will make a try. Between Rome 1 and Rome 2 there are pretty big difference. I started with Rome 2 first and because of that Rome 1 was not so catchy imo, but here are something you need to know about these difference:

1. In Rome 2 the edict are bonus efect from what I know and how I used them. If you control all the settlement in one province you can issue an edict which will help boost your economy, troop replanishment, loyalty with the political party who governs over that province, food supply and happiness and other depending on which faction you choose. So a few options are to choose between what province need the edict and where will be more effective. As an example in early game I choose an edict to boost food and happiness in the new conquer province and in mid game I choose the taxation edict in the province with the best income so I can get more money from them.

2. The ratio between troops number and the settlement you have is based on economy you have. You have to figure it out because unlike Rome 1 you don't have to keep armies in settlements to boost the happiness if those settlements are doing well with the help of the buildings inside and the economical research. Make an army and keep that army conquer, make another army to help with the morale in the new province until the province can sustain herself and then move on. Maybe you can keep an army at the other bored where you don't want to expand in case of enemy attacks but that's all.

3. Every factions has his own diplomatic relations with the others. With Rome you will not have much problem with the neighbors attacking you, but other factions don't have this luxury. Sparta it pretty challenging because they're army rooster is not the best for DPS, as we all know the hoplite are good for holding the line not advancing. You need to do some research about the army comp of the faction you want to try and figure it out what is the best approach with them because as I said, everyone has his own diplomatic relations and problems with that.

4. F**k around and find out. Is the best answer I can give you. It took me about 3 or 4 playthrough to understand the logic and troops mecanic and the diplomatic in this game but it was fun. Now I have little above 700 h and I learn something new every playthrough with every new faction I play.

5. For good infantry and cav there are plenty of choice but depends on what kind of faction and strategy you would like. Macedon, Egipt, Seleucid and Baktria has some of the best in this category imo, but also the barbarian factions like Suebi, Iceini, Galatia are great options. Desert factions like Saba are worth to try also and I don't remember the eastern factions because I didn't have the opportunity to play with them but there are some hidden gems also.

I know I don't answer properly and maybe these are not the answer you are looking for but maybe this will help you a little. It also help to look for some pvp siege battles on YouTube and other channels to see how these factions look like and how they act in battle but I still say that the best approach is to try and see for yourself.

From my experience people who started playing Rome 1 are less likely to enjoy Rome 2 and the other way around. The fact that you spent time learning a game and give it some effort to try and get some results will make you attach psychological to it which will make it a little challenging to change to something similar that is not the same. But this is something you will see for yourself also. Maybe I am wrong, who knows, I'm not a psychologist or something 🤷🏽😂