Here are some things to consider if you're having trouble getting views on Facebook Reels that are uploaded from Instagram:
Audience
Your Instagram followers may not be the same as your Facebook friends, so you might be sharing your reel with different people. You can change your default audience for reels on Facebook at any time, including when you create a reel.
Sharing
You can share your reel from Instagram to Facebook for maximum exposure. You can use "Recommend on Facebook" to reach new audiences on Facebook without a Facebook account, or "Share to Facebook" to engage your existing Facebook audience.
Content requirements
Facebook Reels content must comply with Facebook's Privacy Policy, Community Standards, and Terms of Use.