I've seen that Google treats your mailchimp emails as spam. I just looked at the headers on a few. Passes DKIM and SPF but fails DMARC. Not clear if this is why they get classified as spam, but likely.
dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=jrrshop.com
Moving to a new platform unlikely to fix this unless that includes changes to DNS. Can be corrected by adding a DMARC record to your jrrshop.com DNS configuration in NameCheap.