Sounds like you are doing everything right. I have several ideas you can test:
1. Recently RC released new call handling for users, so this might be having some unexpected side effects for call queues. I don't really know. You can test changing the ringing time for users to 60 seconds. Normally this should affect calls to the direct number and not call queue calls, but maybe it is something that needs to be fixed with the new release. The pathway is
User > click on User > Phone > Call rules & Voicemail > Incoming Calls > Ring settings

2. You can try to create a new call queue with the same users. This could help if the original call queue is somehow glitched.

3. if nothing works, you can attach screenshots here of the Call queue settings (working hours and wait settings) or contact support

4. Judging from what you have said the following is unlikely but it is also something that would be difficult for us to diagnose without looking at your account - and that is if you have set incorrect call handling. for example if the call is not hitting the queue at all, but is going to a ring group. or if you have custom rules, overriding the sequential call handling you have set, etc. Again it might be worth it to reach out to support.

@Welcome 01 Thank you so much. I will troubleshoot with your suggestions. Thanks for your help.