1. compress to mp4
2. install telegram on your computer and on your phone
2. on your computer, open telegram and send the clip to yourself (it's called saved messages)
3. open telegram on your phone and download the file (when you read the clip, use the share button, then save to camera roll)
4. you can upload to insta
this way you don't loose quality.
there are also other ways (wetransfer, airdrop, emailing to yourself, dropbox, ...)