It will not lead to your account being banned. It follows the same reasoning as before. If purchasing followers and likes resulted in bans, everyone would simply buy them for their competitors to get them banned.
Those who claim it will result in a ban usually say so because it makes sense to them or they heard it from somewhere. However, it is merely empty talk. One of the major issues in the world is people pretending to have knowledge about a subject and confidently stating their opinions.
The possibility of experiencing reduced reach may be true, but I am uncertain if it applies to TikTok since I do not know its algorithm yet.
Buying followers can be beneficial, particularly when your account is new. Having more followers makes you appear more popular, increasing the likelihood that others will follow and interact with you. However, it is important to note that buying followers, likes, and views should not be seen as a substitute for genuine efforts to grow your account organically.