Why am I not getting notifications for texts or calls on my iPhone while I’m on TikTok or Netflix?

I have not been getting notifications for texts or phone calls while I’m on TikTok or Netflix on my iPhone . I do not have do not disturb enabled so I can’t figure out what the issue is. This has already caused some problems in my life (both personal and professional) because of my extremely late (or no) responses regarding important things. Please can someone help me figure this out? I am up to date with iOS and am currently using an iPhone 12 mini.I really don’t want to switch to an android phone but if I can’t resolve this huge issue I might just have to do that. Please help me. Ps it’s 05/05/2024 when I’m writing this message.