It is safe. Telegram only bans specific communities it finds engaged in piracy, and even that it does very slowly, mostly under legal pressure. No user accounts have been banned for that, ever.
It’s also worth noting that Pavel Durov, the man behind Telegram, has previously created the famous VK social network, and up until he was kicked out of director board, he fought for free (including pirated) music on the platform.
Worth noting that the absolute best quality Deezer has is 44,1kHz 16-bit lossless, and most songs there are MP3 anyway.
If this is good enough for you, absolutely go for it. If you’re looking to download high-quality music from a streming service, you can use tidal-dl (or tidal-gui for more convenience) combined with Tidal - though it’s worth noting Tidal has been subject to some controversies regarding some of the master quality albums, too.