Default build would be something along the lines of.

Hill Dwarf, any background (if unsure pick sailor)

S: 14, D: 10, C: 14+2, I: 10, W: 15+1, Ch: 8

Increase Wisdom at level 4 to 18. Wear chain mail and wield warhammer + shield or great maul. Be Magni Bronzebeard and thunderclap everywhere.

If you want to really abuse RAW, then go variant human with following stats:

S: 8, D: 15+1, C: 14, I: 8, W: 15+1, Ch: 8 (then make either Str, Int or Cha 10).

As your level 1 feat, take spell sniper. This gives you a free cantrip, and doubles the range on all spells which require you to make an attack roll. Take Booming Blade, from the SCAG (it has a range of 5 feet and requires an attack roll, giving it a range of 10 feet).

Use a whip and shield. Cast booming blade, then make an attack with your whip against an enemy 10 feet away (which is possible because the Whip has reach). Booming blade adds some thunder damage to your attack, but also does even more thunder damage if the target moves before your next turn. Because they're 10 feet away, if they want to come closer to you (or run away), they will take more damage. If they do get into melee range of you and hit you, you can do 2d8 lightning damage to them and push them back 10 feet, repeating the cycle.

Take +2 Wis at levels 4 and 8, then either raise dex or take feats (consider warcaster, for the ability to cast a spell as an opportunity attack, further locking down your target from running away).