Would you be kind enough to suggest a travel plan from Dongguan to Repulse Bay Hong Kong?

You can take the cross border coach from Hotel Silverland, DG Hillside Hotel, or the Overseas Chinese Building. Coaches arrive in China HK City or Kowloon Tong.

If you arrive in China HK City, you can take bus no. 973 from China HK City, Canton Road to Repulse Bay Beach, Repulse Bay Road to reach.
If you arrive in Kowloon Tong, you can take bus no. 103 from Kowloon Tong Station, Waterloo Road to Murray Road, and transfer to bus no. 6 at City Hall, Connaught Road Central, and then get off at Repulse Bay Beach, Repulse bay Road.