Are they bad on video or are they bad when uploaded to YouTube? (Or something like that)
If it's only bad quality on YouTube, then you'll have to upscale it, when editing to 1440p.
When uploading a YouTube video in 1440p, YouTube will make it run with a good encoder, if you'll upload it in 1080p, YouTube will give you a bad encoder for that video. If it's not just on YouTube, but on video too, try to increase your video bitrate a bit.