Try a cable offload. It is fast and safe.
Connect your phone to a computer. Import all photos and videos, select delete after import. On Android, move WhatsApp, Telegram, and Downloads folders. On iPhone, use Photos or Image Capture on Mac, or teh Windows Photos app.
Next, purge offline downloads inside Netflix, YouTube, Spotify. Clear cache in Instagram, TikTok, Telegram.
Reboot. You free tens of gigabytes on most phones. Example, one hour of 4K video is about 24 to 30 GB. Repeat monthly. No new apps, fewer permissions, fewer ads. Done. Dont overthink it.