Ok, you are starting at 7th level so you have two feats to start with. Since you are starting with those feats you can take an odd number in something a fill in with a fun feat. Take a feat instead of an ability increase, feats define your build and are far more fun to use.
Dual wielding falls behind on damage because to get that extra damage in you need to use a bonus action. There are many things that will use your bonus action so you wont be able to make that attack. In addition, the Great Weapon Master feat exists which allows you to take -5 penalty for +10 damage, that pushes great weapons over the top. This also make Polearms great, because you can then take polearm master feat to get back the bonus action attack (same as dual wielding) and get more OPP attacks. Since you are starting at 7th level you can just go polearm and start with both for max fun. Your STR will be 16 if you do this, but with bounded accuracy it doesn't hurt that much considering the versatility you get, and it would only be for level as you get a ABI at 8th level.
Another build that puts out better than expected damage if done right is shield users. You take dueling as your fighter talent for +2 damage, that pushes d8 weapons to effective d12, and then take Shield Master as your feat. When you declare your attack action you can take your bonus action first to shove with shield to try and knock them prone, attacks against prone creatures are with advantage so you will hit more and do more damage and do more critical hits. Using your bonus action to shove is a good deal and worth the feat by itself; in addition you get all those other benefits. You will prone more than think since its a STR check and you are proficient. Talk to your DM also, my DM agreed that as a fighter you are proficient in using a shield to bash someone with damage as a club but then you lose your +2 to damage from Dueling fighter talent for that turn for more flavor.
Don't worry about DEX if you are using heavy armor, the bonus doesn't apply.
Since you are starting at 7th level you can MC, a high risk/reward fun build to dual wield in is Barb5/Ftr2. The barbarian bonus damage when raging will stack with dual wield talent from fighter, yielding +6 with your dual wielded battle-axes from Dual Wield feat. Your STR would only be 16, but you can reckless attack to gain advantage on your attacks. You would need to go STR 14 (16 with Dwarf), Con 14 (16 with Dwarf), 14 into Dex (you will be wearing no armor or medium armor so +2 dex will help). Your base AC is 15 until you get good medium armor.
Also since you are starting at 7th level and have those 2 feats in the bag, you can start with 17 STR total and 15 in CON total, and then for feats take Heavy Armor mastery to get the + STR back and the damage reduction of 3 against B/S/P, leaving a feat for something fun. Yes your CON will only be 15, costing you 7 HP and +1 to your saving throws, but you will get that back and more in damage not taken the first 3 times you get hit. This still gives you a 18 STR and a feat for fun like GWM or Polearm Master. This works better well with any build, but is worth more with a polearm or great weapon fighter since without a shield you will get hit more. Heavy Armor Mastery is a very good feat and holds it value as at higher levels you will get hit round after round. At level 8 you can just boost CON with the Durable feat. I played this from level 1 with variant human using a halberd and polearm master and it was great fun.
Polearm Master loses some value with Great Weapon Master feat, you need to keep your bonus action available in case you get a crit or kill to have that bonus attack. Watch you positioning with GWM feat, make sure you are always in position to take that bonus attack if it comes. Some conditions grant auto-crits, so be ready for that if you have GWM.
