Explanation for anyone who needs it:
"My Shayla" is a meme on tiktok derived from a video of actor Tyrese Gibson crying on an Instagram Live about losing custody of his daughter Shayla. It is generally used as a sound for people missing a person, a space or time (eg. your childhood), or just thinking about their pets while they're at work. In this case, Tiktok is replacing Shayla for the OP.
Many US users of Tiktok post-ban have commented that their algorithm is less personalized and more geared towards outrage content. As such, the app no longer has the original vibes, and is now suspected as another delivery method of propaganda for the Trump administration. They are now seeking alternatives.
To express their disappointment, another user is saying they have had a "no bones day" since the return of the app. This refers to a famous pug named Noodle on Tiktok who's owner posted videos of them lifting Noodle up and seeing if Noodle will stand up on their own or fall over. If Noodles stood up, it was a high energy therefore "bones" day, and if Noodles fell over, it was a low energy "no bones day".
The final poster makes a humourous observation that without Tiktok, they would not have understood the previous conversation, and wishes "old Tiktok" to rest in peace.
Some additional nice commentary: Older observers have chimed into this conversation reminiscing about their own "lost" or enshittified websites and platforms (stumbleupon, addictinggames/other flash sites, Homestarrunner, Vine, MSN Messenger, MySpace, Encarta, Napsters, Last. fm, hobby forums, etc.) They have tried to assure younger people, who socialize more online than any other generation, that there will be other options and opportunities to gather in communities again (to mixed results).