As someone who frequently receives calls and messages from unknown and unverified numbers, I know my phone number is already in a scammer’s database. When I first received a suspicious message like that, I immediately unlinked that phone number from all the platforms I use, but I still keep the number because I’ve had it for a very long time. As for the numbers I use for exchange accounts and the like, I use a postpaid number that I don’t use very often and that has an anti-spam feature.
So we just need to be careful when receiving messages or calls from unknown numbers. Scammers these days are so sophisticated that they can even mimic people we know using deepfakes.
It's not only about us using our phone numbers on platforms that we use, sometimes these scammers get our numbers directly from our network providers. The companies that sell us these numbers also sell them to advertisers so that they can send us messages, promote their products and services, etc. Maybe major companies avoid doing this because it might get them in trouble if someone sues them for doing so, but a lot of companies do sell their user's data or at least share them with other firms for advertising, and that is how we often receive messages and calls from companies and services that we have never used in our lives.
I'm not saying that scammers get our numbers this way, but they must be doing it in a similar way where they pretend to be a service provider or something and gain access to a list of numbers, and then they use those numbers for their scams, because it is not logical to think that scammers just randomly enter phone numbers and send messages or try different random numbers on call so that if they connect, they can try to scam them, and also, most scammers already know that you use a specific service or platform, how is that possible without prior information?