My contacts are not synced on my iPad. Some of the contacts are missing. Cannot fix it on iCloud

Welcome to the Apple Community.

Please try the following…

1. First check that all your settings are correct, that contact syncing is checked on all devices (System Preferences ➔ iCloud ➔ Contacts ➔ On on a Mac and Settings ➔ Apple ID(Top) ➔ iCloud ➔ Apps Using iCloud ➔ Contacts ➔ On on an iPhone, iPad or iPod).
2. Make sure the contacts you are adding are added to your 'iCloud' group and not an 'On My Mac', 'On My Phone' or other non-iCloud groups (you can do this by checking in groups), non iCloud contacts will not sync.
3. If you are sure that everything is set up correctly and your contacts are in the iCloud group, you might try unchecking contact syncing in the iCloud settings, restarting your device and then re-enabling contact syncing.

I suggest that you start by verifying that you have iCloud syncing properly configured on all of your devices that you log into with the same Apple ID by reviewing the following article: Set up iCloud on all your devices - Apple Support

I am concerned that I actually have two Apple IDs, BTW. I know that may play a role here.

Yes, it definitely will. To successfully sync between devices, each must log into iCloud with the same Apple ID.

Point 2 kinda covers that. If you have 2 accounts, use your Mac to resolve the matter. You can drag the contacts between accounts.