Tdarr is what I use to unify my media. It does a good job of converting my files to h265. Runs in the background with my tesla p4 transcoding 3 streams at a time. Ripped through my 30ish tb library in a few days. It can change bitrate and resolution as well, but I haven’t had the time to play around with that yet. Can watch you library for change and transcode automatically, or you can run it when you like.