Don’t consider yourself an island on TikTok. It is, after all, a social network, so you must socialize with others. Reply to every comment that people leave on your videos. Watch other peoples’ videos (preferably in your niche) and leave thoughtful, interesting comments there, that can spark an ongoing conversation. Avoid spammy type comments such as “Nice video.”
Look for other experts in your niche and try and collaborate with them. You will usually find it easiest to do this with other broadcasters of a similar size to yourself, or perhaps a little bigger, check this link. You are far more likely to get agreement from them for collaboration than if you try and work with the big names of TikTok who probably receive many offers every day.