Music

In terms of websites, I think either would be fine, but I'd make sure you have a version (like the youtube you pay for) to ensure there aren't random ads popping up in your music.

But in terms of a DJ, they are more than just there to play music. They make announcements, they keep the reception flowing and help people know what's going on, ours has a detailed outline/timeline for grand entrance, first dance, parent dances, blessing, speeches/toasts, etc. But more than just that, he knows how to read the dance floor to know if he needs to swap genre and songs and how to make the music flow to keep the party going. Just a few things to consider if you're wanting that type of flow.

Get Spotify Premium so you don't have to deal with ads. You don't need a DJ. Especially if you are wanting a low key event. If you need someone to announce things just get a lively family or friend to handle the mic. You can also rent large Bluetooth speakers. DJ's make sense if you are having a traditional wedding to keep the flow of the evening. It doesn't sound like you will need that.

I wasn't saying you should get a DJ, just to consider those other aspects that a DJ provides, make sure you have someone who is able to make sure everything flows.

We're just making a Spotify playlist to play over the speakers at dinner! We're working out ceremony music (if any), but will just use Spotify or YouTube premium for that as well!