A good video editor on Android is hard to come by. Most Google Play Store video editors are ad-infested, add watermarks, have terrible UI, work poorly or are sketchy clones of each other with fake reviews.
InShot is one of the best I tried but Google Photos is a simple alternative you probably already have installed:
- In Google Photos, select videos you'd like to edit
- Click + button and create a Movie
- Click ♪ button to remove / change the music
- Use scrub bars below to trim the videos
- Click Save when you're done
This produces a Movie which you can download (mine was Full HD) - might have to wait a bit while Google generates the file on the server.
There are a few issues with this approach:
- Without music, there's a 0.5 sec silence between the videos
- Limited editing controls, no effects, stickers, etc - if you're into that
- Output resolution / compression is not adjustable