My Gmail/G Suite account got disabled, is there a way to avoid this happening on my end?

You'll generally see errors like this if you get too many spam complaints or push the daily send limits of the account. Our suggestion is to keep within the send limits of your email provider and send content that is relevant to your target list.

Here are some suggestions: 

• Make sure you correctly warm up your email account for at least 30 days.
• Keep your send count within the send limits of your email provider, (500/day for Gmail, 2000 unique recipients/day for G Suite [not in trial period & $30 paid balance], Office 365's Outlook: 10 000/day.)
• Send content that is relevant to your target list.
• Use as many custom Merge Fields as possible, so that your emails stay as relevant as possible.