Contact List Won’t Sync Completely

I have Contacts turned on in iCloud on my iPhone, iPad, and MacBook. All are up to date and running the latest OS and iOS. However, despite syncing with a cable as well, about half my contacts on my phone are missing on my iPad and computer. When I look at iMessages on these, there’s no name for contacts I’ve had for years. How do I fix this without having to manually add hundreds of contacts to these devices?