This is how I see it and its 100% my opinion only:
IG - Reels, stories etc = For the flash, for the pazazz, for the lux life. If you have big mommy milkers, you got that influencer house, or want to sell your polished product, you do so on IG. Big on aesthetics, lifestyle, and influencer culture, highly edited vibe.
Tiktok: Superficiality dies here, for the most part. It exists but it doesn't thrive. This is for your day to day person, the raw, authenticity beats perfection. The mom thrives here, the worker, even fast food workers can gain a huge following here. Not polished and your half assed product can sell very well here. If you're informative, you will win.
Facebook: Community based outreach, nostalgia, and “share if you agree” posts dominate. Boomer traditionalism, MLMs, and outrage driven content still have a massive hold on the minds of the Facebookers.
X: Can you lie your ass off? Go here to make money. The more confidently you can spin a narrative (true or false), the better you do. Hot takes, controversy, and engagement farming are how you win.
Not sure if this is what you asked but there ya go.