I purchased an item nearly 15 hours ago. The item appeared in my shop inventory shortly after, but the icon is grayed out and I can't interact with it. I'd like to be able to withdraw it. I read a few other support threads about this issue, but am uncertain what to do. Should I just wait it out and hope it becomes withdrawable in a few days?

If the bot cannot send you a valid trade offer after 3 retries, probably because steamcommunity website is down, or other reasons that cause the bot cannot send you the trade offer, your items will be temporarily locked from retrying in order to avoid hammering steam and its related services. The lock will be lifted within 24 hours and it will retry afterwards.