There is a way to apply the plugin settings to existing embed videos automatical

You do not need to edit your embeds, ARVE automatically adds parameters to the embed URLs you can edit them on the setting page. Defaults below already includes rel=0, but YouTube sucks, they removed that feature. They now force related videos on the end now. What this setting does now it shows only related videos from the same channel, not from other channels.

iv_load_policy=3&modestbranding=1&rel=0&autohide=1&playsinline=0