Dual Sim iMessages not coming through

My work was starting to overtake my personal life, so I purchased an additional line from AT&T and set up a “business” line on my iPhone 15 Pro Max using the Dual Sim. The idea was that I can turn off the business line during non-business hours. Pretty standard concept I wanted two separate phone numbers operating on the same phone. It has been great, except I recently learned that text messages sent to the business line when it was turned off do not come through when I turned the line back on. Lots of searching makes it seem like this has been a known problem for years, but I can’t find a solution. Any help would be greatly appreciated.