I would use RAW for shoving.
[ +- ] Shoving Rules
Shoving a Creature
Using the Attack action, you can make a special melee attack to shove a creature, either to knock it prone or push it away from you. If you're able to make multiple attacks with the Attack action, this attack replaces one of them.
The target must be no more than one size larger than you and must be within your reach. Instead of making an attack roll, you make a Strength (Athletics) check contested by the target's Strength (Athletics) or Dexterity (Acrobatics) check (the target chooses the ability to use). You succeed automatically if the target is incapacitated. If you succeed, you either knock the target prone or push it 5 feet away from you.
Variant Human is allowed, as are any classes or subclasses available on DND Beyond. I may have initially said published, but I feel like its a game that's meant for fun. We can make it work. :) You may want to look at the Supernatural Gifts section of the Theros book (len has access to a legendary bundle if you like); having said that, one of them is access to a feat.