I am currently in the Early stages of development of my game where I don't need to care about Leader-boards, Commerce, Player Segmentation, and other stuff. I need to get the Game up and running, and the Free Tier is perfect for this stage. Unfortunately, We cannot use the new Thunderbird servers in the game manger in the free tier.
I understand that you cannot giveaway resources for free ,So what I am suggesting is,allow the developers to use the Thunderbird Servers even in free tier and Bill them per hour as usual. Once We're confident about the core game, then we'll move on to implementing Leader-boards, In Game Commerce, Clan System, for which we'll move to the higher Tiers.
I have been suggesting Playfab in my workplace for our current Project we just started , but this is a major hurdle for us as it doesn't make sense to spend money on Services we wont be using yet.
Thank You! Hopefully this can be implemented soon!