Open Samsung cloud app.
Scroll down to the bottom of the page and you should see three options, Backup this phone, restore data and delete backup.
Select restore data. Clear the checkmark from the All option and then select contacts from the list. Restore.
This method will only restore your contacts.
We can restore data for third party apps using the same method by tapping the right facing chevron next to the apps title. It opens a page where we can select only one app or two to restore. I hope this helps.
If we open Samsung cloud and select restore the messages app entry displays the number of messages we have backed up.
If it shows a good number of messages backed up but doesn't restore them it might have an issue with connecting to the database and retrieving them. I will test mine in a bit. I'll back up my messages, delete all of them, use restore and let you know the results. Errands to run back later.
Galaxy S9 SM-G960U
Security Patch Level
March 1st, 2020
I backed up my current messages, it added the new messages to the previous backup. Samsung cloud shows I have 30 messages backed up.
Opened Samsung messages, deleted all messages and closed it.
Back to Samsung cloud to restore them. It restored all 30 messages. I counted them to make sure.