channel.subscribe merely reports that a subscription has started.
channel.subscription.gift will report that someone gave gift(s) (but this won’t include the recipient just the count)
Depending on your use case there are a lot of what ifs involved here.
There currently isn’t a topic that will describe all three entities involved (channle, gifter, reciever)
This is uservoiced here channel subscriptions to include who gave the gift if it's a gift – Twitch UserVoice
And theres also a longer uservoice here Revise the `channel.subscription` topics – Twitch UserVoice about reorganising the whole subscription topics into something more useful for overlay providers/usecases