Two very different limits
Send a video from your Gallery and WhatsApp automatically compresses it, capping inline video around 16 MB. That keeps it playable directly in the chat, but WhatsApp's own compression can visibly soften quality. Send the same file as a Document instead and it goes through mostly untouched, up to a 2 GB ceiling, but the recipient has to tap to download it rather than watching it inline.
Compress on your terms instead
QuickCompress lets you choose the outcome before you send: pick a target size under 16 MB for an inline-quality clip you control, or just shrink a large file enough to attach as a Document without a multi-minute upload. Either way, the encoding runs locally on your Mac, and your original file is never modified.
Related
Sharing to Discord or a work Slack channel has similar size ceilings. See compress video for Discord and compress video for email.