Make an alternate account. Seriously.
If you make a silver account, having a gold account on your Xbox upgrades it to gold automatically. I made an alt to search alone with, and my main account to play with full parties. It allows me to search solo without having anxiety about my ranking.
The nice thing is that you can sign in with both, so that you can search solo with your alt while still receiving party invites and such on your main. The only issue is that with Halo 5 Beta, you have to manually quit the beta whenever you want to switch accounts, but it’s not that big a deal.
Hopefully this helps some of you with your “this game gives me trash teammates” woes.