My thought is that the more active someone is on X, the higher the chance they'll respond to a DM. If you have their X handle, you should be able to find their mobile number through other sources. X is a good way to warm up cold leads and find interesting prospects in new areas. While I wouldn't say it won't work, my personal experience with X DMs makes me a bit hesitant due to the amount of spam and sketchy offers.
I think Shopify owners might be the most receptive, given their entrepreneurial background.