Basically, Swordsman1 -> Peltasta2 -> Whatever you want as long as it can equip a shield, is the current meta for PvE Swordies.
Pelt2 gives you the ability to taunt large groups of mobs (Provided you have a shield equipped) which makes soloing a lot easier and gives you some party utility in case you ever decide to do group content (Which you really should. It’s the fastest way to level once you reach 100. Keep an eye out for Challenge Mode parties if you want to get to the higher levels in a hurry). It also has a skill called Guardian which increases your Physical and Magic Defense by 100% so survivability won’t be an issue.
On a general note, classes that have a red icon are focused on DPS, blue ones are primarily defensive in nature, green ones prioritize support in some way, yellow classes are either crafters or allow you to set up some kind of shop that other players can get items or buffs from, and purple ones rely on summoning pets.