You could slap together a script that tracks the current ratios of a given index fund, then maintain a blacklist of baddies, and automatically buy at the new ra

You could slap together a script that tracks the current ratios of a given index fund, then maintain a blacklist of baddies, and automatically buy at the new ratio using something like alpaca.markets api for buying. You'd get all the expertise of whoever designs your index of choice but your custom little changes for removing companies you want to ethically avoid.