You're bottom bracket might need work or replacement, but the fact that it continues when you stop pedaling points elsewhere. When you're not pedaling, the only parts of the bike that are moving are the wheels and the freehub, If the noise disappears while start pedaling, then the wheels are OK.That leaves the freehub, also called the cassette body, which is the ratcheting part of the hub that allows you to coast. Remove the wheel, rotate it as if coasting and as if pedaling, and confirm this.
In general, I don't advocate freehub overhauls for beginners. Even freehub replacement often requires a full hub overhaul, a matter I can't resolve without examining the hub. I recommend taking the wheel to a shop. But if you insist, there are videos on YouTube and plenty of subscribers to this forum who will try to walk you through it.
Last edited by oldbobcat; 10-02-22 at 01:30 PM.