Sharing Xbox live gold with multiple profiles?

They have; it'll be replaced soon by shared Xbox Live Gold which will allow multiple accounts (on the same console, I believe) to use another profile's Gold membership for the one subscription.

By putting the account as the main account, you can share both gold membership, games and other services

I tried unplugging and restarting my Xbox and it still won't work. The weird thing is that I can play the games that i downloaded through Games with Gold but I just can't play online or join/make parties.

As long as your console is set as his Home, you would be able to access their gold without them needing to sign in. If it is set up correctly, try holding down the power button on the console until it turns off, unplugging the console, plug it back in, then
restarting it.

Also, keep in mind that sharing account information is a violation of the code of conduct/terms of service even if they are family.

I have an Xbox one x, and a Xbox one s in my home. In order to achieve full functionality, both accounts need their own subscription.

Not exactly. The account with the gold/games can set one console as their Home and then sign in an use the non-Home console. Unless there are multiple people that have to use both consoles or you have more than 2 consoles, you only need 1 subscription.