The Galaxy A53 5G comes with two text messaging apps (Samsung Messages and Google Messages). Therefore, the steps to set a different sound for text messages vary depending on which app you are using.

i. Samsung Messages

1. In Samsung Messages, tap the three-vertical-dot Menu button > Settings > Notifications > Notification categories > New messages > Sound
2. Select a sound.

 
ii. Google Messages

1. In Google Messages, tap the three-vertical-dot Menu button > Settings > Notifications > Notification categories > Incoming messages > Sound
2. Select a sound.