Sync contacts between iphone and icloud...??

Take help of a web browser and enter in www.icloud.com with the apple id and password used in an iOS device , the contacts that were saved in will be visible select the desired contacts and click on gear icon in the left bottom corner and click on export as v card .

Open finder , click on downloads , right click on .vcf file and open with contacts .app( default ) .

The address book will get opened , a pop up window will appear stating are you sure you want to add number of cards , click on add .

Again open your address book the contacts that were in the iOS will be transferred under the section “ All contacts “ in the Mac address book .

Sign out from www.icloud.com used with Apple ID and password for an iOS device .

Then enter in www.icloud.com with the apple id and password used in the Mac , click on gear icon and click on import as v card all the contacts will be transferred in the iCloud server , click on create group on the bottom right corner an untitled folder will be created in the side bar and the contacts from iOS are all transferred to the iCloud server account .

See some articles  iCloud: Export a contact as a vCard from iCloud Contacts

iCloud: Import a contact into iCloud Contacts

iCloud: Create a group in iCloud Contacts

If you are using a gmail account and both iOS device and Mac are signed in with same Apple ID and password then contacts will get merged but will it take hours and totally depend upon your network speed .

https://support.apple.com/en-us/HT205754

And you have to always be signed in with same Apple ID and password in an iOS device and Mac .

If in any case both devices are not signed in with same Apple ID and password then you have to follow the steps in the above first post you can send a feed back https://www.apple.com/feedback/

Perhaps , you can't create a group in an iPhone as the data base is very less as compared to Mac , as apple engineers have designed in such a way .

You can create a group in your Mac and name as per your choice say iOS contacts or whatever see this article https://support.apple.com/en-in/guide/contacts/create-groups-adrb3280fe91/mac

And that will differentiate the other contacts , you can drag and drop contacts in this group as per your convenience .

The following may help: Get help using iCloud Contacts, Calendars, or Reminders - Apple Support

The most common reason that contacts don't show up in iCloud is that they are in a 3rd party account (Gmail, yahoo, etc). That is discussed in the previously supplied link. It also has limited information about importing those contacts.