I was thinking more from the perspective of a dex-heavy bard for a melee option. OTOH, it's not hard to end up with 16 or 18 in everything by the end, but damage would suck early on.
BTW, what is the d6 from Striking? Do you mean the magic item? Is it assumed you can get that, generallly? Where are the rules for Elemental Runes?
Magical weapons have two types of runes on them: fundamental runes, which are what make the weapon as such better, and property runes which add additional abilities. Fundamental weapon runes come in two further categories: potency (+1, +2, or +3 to hit) and striking (1, 2, or 3 dice extra weapon damage – so a
striking battleaxe would deal 2d8 damage). Property runes are basically everything else you can do with a magic weapon, e.g.
ghost touch,
returning (on a thrown weapon), and so on. Quite a lot of these add 1d6 energy damage of some sort (
flaming,
frost,
shock etc.), and these are colloquially called elemental runes, and they make pretty good runes to default to – basically, if you don't have a special plan intended for your weapon (like
returning on a throwing weapon), you won't go wrong with an elemental rune for some extra damage. You can have a maximum of one property rune per "plus", so a +2 weapon can have two property runes.
Potency/Striking runes are an essential upgrade for every character who intends to actually use a weapon. Without getting those at the levels where they become available, you will lag behind quite a bit when it comes to combat ability.
Oh, and bards generally don't make good melee combatants in PF2. Bards are full casters, with the weapon proficiencies to match, meaning they only become Expert in their weapons at level 11 and never become Masters in fighting. Even the bard subclass that's supposed to be good at combat (Warrior muse, from Advanced Player's Guide) only get
broader weapon proficiency, not
better. I mean, it's not wrong for a bard to have a weapon for use when they have actions to spare, but swording opponents as a bard is at best a plan D (with plan C being arrowing them instead)