Bangkok - (transfer in Shantou) - Chengdu - Hong Kong, is this a problem?

Hi there, I will be in China for less than 24 hours but my routing is Bangkok - (Shantou, transfer) - Chengdu - Hong Kong. Do I still need a visa?

Below is my flight details, can you please confirm if a Chinese Visa is needed for this route for UK passport?

Bangkok BKK > Shantou SWA > Chengdu CTU

Depart Bangkok: 11:30am
Arrive Shantou: 3:20pm

CONNECTING (2:15 transfer in Shantou)

Depart Shantou: 5:35pm
Arrive Chengdu: 8:20pm

NEXT DAY

Chengdu CTU > Hong Kong HKG

Depart Chengdu: 1:55pm
Arrive Hong Kong: 4:55pm

Thank you so much for your help!!