I am a M30s user I am actually figuring out a way to enable carrier aggregation in M30s And other phone if I find a way to do so I will share it on Samsung members
No other way, only official way to get carrier aggregation in m30s is, Provide feedback to samsung developers via feedback section(ask questions section), they need a minimum no. Of feedback from unique users (respect to no. of sales of device across all platforms), to add a premium feature. To provide feedback in samsung members app, Open Samsung Members Application > Get help > Send Feedback > Ask questions. If you want quicker action, write on every channel, whatsapp, samsung members app - ask question and error report, ceo escalation desk, service head desk, call toll free no. , support email of samsung, youtube, samsung content help( google it),samsung live chat,twitter, instagram,facebook,linkedin,etc. It is the power of our feedbacks only , that samsung started to give clipboard in many devices.
Carrier agg. will show in form of plus +sign only if your sim supports and you are in a high network zone even in my phone the 4g+sign doesn't always stay on it fluctuates between 4g and 4g+
