I am afraid there is no alternative settings for Viva Connections to load first when Teams startup.
To achieve this feature, you could try to give the feedback in Teams UserVoice. Microsoft will always focus on customer’s feedback and experience, some new features would be added to the services based on customers' feedback in the future, and your good ideas will be very helpful for them to improve the service. Your time, understanding and cooperation will be highly appreciated.
Thanks for your understanding and patience!
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