How the hell did they know my personal accounts/phone numbers?

I’ve been getting weird emails or being added to random WhatsApp or Facebook groups lately after I started getting involved with cryptocurrencies even though I registered my wallet using a different phone number from the one I use for my WhatsApp and other daily personal activities. So how on earth could these groups (or I believe some are companies since they are trying to sell me stuff) know I’m buying crypto then? Is this a sign my cryptos are in danger? Should I change wallet or do something about my coins?

Also, does which wallet I use really matter all that much or are they all basically the same if you’re not using them for transactions? I know cold wallets are ideal, but I don’t have the means to buy one at the moment (shame).