Hello,
Those Questions may have different answers depending on opinions , i will leave mine , it may can help.
1-While Swords are faster , Maces deal the most dmg but they are slow if you have attack speed on your gear it can improve you attack speed on that kind of weapon. Axes are balanced between attack speed. But it depends on your class, while defense shines with blungeons , rogue and warfare can do very well with swords.
I may sugestess to play a bit with swords/maces and axes to see whats gives you the best result.
2-You can create a mule character, by creating a acomplish hero at lv 40, it have all 3x bags already avaliable to store your goods. Also Vault is a external tool that do same function.
3-Yes. Relics and Charms are a important factor ingame. To make artefacts and to use when you need, in case, if you need a boost on your resistance for exemple. Some relics can ahve a great completion bonus. Its always good have then around.
4-Its depends on your style. I can say every skill can be important depending the situation. Auto attack replacers are important to be maxed as fast as possible or AoEs.
5-I been using Pure Str on my Mellee characters , those who use axes and maces. I mix with Dex for spears and Throw weapons. Staffs pure Int. While bows only dex. a bit mix on dex may be necessary for some armor requeriments.
6-It depends. Some charms are easy to farm , like boar hide, venon sac. You only recover if you feel that relic is strong or have a great completion bonus.
7-Pierce and Bleeding resistance. Another way is doing skill combos, like sand of sleep then squall on their face
8-I dont remenber what are those. But i assume its for unlocking the Secreat passage on Ragnarok Act.
9-Tartarus is like Diablo Endless Rifts. you face waves of random enemies then move to next room. But you have random penality during the batle. Like less resistance on some element, enemies are bigger or drian mana. in the end of 3 rooms or 5 i dont remenber exacly, you face a boss (Tartarus), when you kill him he drops a boss orb, the 1st time will have less % to drop blues/purple. But the chances will increase after you defeat each Tartarus boss. Its not worthy doing Tartarus becuase its not provides a good performance and it have some instabilitie , monster spawns under the floor and crashes.
10-It depends , if your character is strong can go right to Atlantis before going into Hades act. but i think its better to go before ragnarok. Or When you are half way into Hades act.
11- Hard to say, you do your normal play throught the campaign, if you find a wall or getting killed to fast, you can do boss runs in the earlier acts to see if you can find a good equipment. Normally in Epic+. ON normal inst necessary at all.