1. Buy from distributor, st-link or nucleo board :
https://www.mouser.de/ProductDetail/STMicroelectronics/STLINK-V3MINIE?qs=MyNHzdoqoQKcLQe5Jawcgw%3D%3D
https://www.mouser.de/ProductDetail/STMicroelectronics/NUCLEO-F103RB?qs=fK8dlpkaUMs2W6dqxUbL2w%3D%3D
2. If want cheap...from Ali or so, look for comments, that show: this is original STM on board.
I have some BluePills with STM32 chip, but also 2 with CKS32 ... so read description carefully and comments.
If no comments, that say "original STM" or "works with stm32IDE " , dont buy this.
eg.
Recently i buy this :
https://de.aliexpress.com/item/1005006246566896.html?spm=a2g0o.order_list.order_list_main.5.21ef5c5fzMlpCu&gatewayAdapt=glo2deu
Seems original STM chip, can debug in IDE . But at your own risk -- sometimes the chinese sellers get new parts - they dont know, and you will know, when you get it and test.