It helps that you have the accounts on different emails.
Proxies actual are detectable if used incorrectly and so not using one can be safer.
The reason most people get frozen is through transferring items. Then scoresending and abing. It seems like you're main purpose on playing on the other accounts isn't to just make nps, so it would make the accounts seem legitimate. IPs are shared by location so they can't just ban all your accounts based on shared IP.
Just don't be greedy and keep doing what you're doing.