When it comes to mobile game development, most companies prefer remote workers as they are cheaper and fit into the budget.
Freelancer groups like Upwork and Fiverr benefit the freelance workforce. You can find the best mobile app services on these platforms with the skills you need. You can monitor the work of the hired freelancers directly from these platforms. But the main risk in hiring the freelancer is their availability and code quality. However, they may delay the work or ghost on you at the last minute.
You must consider the experience before deciding which option to go for. Most development companies have diverse experience. I would recommend going for a game development company as it is reliable, delivers quality work, maintains code quality, and meets deadlines.
Freelancers are pretty unreliable, even if they are cheap compared to agencies. So when you are trying to hire mobile game developers, then you really need to look for agencies and not freelancers since the latter can screw you up big time. They often don’t have full teams and neither they have any major market credibility. Any experienced app firm won’t go for it and neither would it be approved by your app investors.