Restrict contacts from knowing I am on WhatsApp
Simple answer to your question is - everyone who has your new number will see that you are on WhatsApp. WhatsApp is tied to mobile number only and it will not "broadcast to any other sim". If you don't give this number to another person then they will not be able to  see or contact you.

Also a hint. If you have dual SIM phone you can use normal WhatsApp and business WhatsApp (it's free) on the same phone simultaneously (using 2 different numbers).