Video Quality Down after Edit?

I create and edit Gameplay Videos for TikTok and normally I edit them via CapCut. I add contrast(+ 10) and sharpen (+ 100) twice to my Videos. Export them with 4k. So when I upload them to TikTok, the Quality is really sharp. But since yesterday the Quality went down? I updated CapCut but the Quality is still bad? I didn't change anything and also deleted my cache and my drafts but I can’t get the sharpness back?! Please help!!

I create and edit Gameplay Videos for TikTok and normally I edit them via CapCut. I add contrast(+ 10) and sharpen (+ 100) twice to my Videos. Export them with 4k. So when I upload them to TikTok, the Quality is really sharp. But since yesterday the Quality went down? I updated CapCut but the Quality is still bad? I didn't change anything and also deleted my cache and my drafts but I can’t get the sharpness back?! Please help!!