Dual Sim + LTE-watch

Hello all, I want to try the following:

• Iphone 12 Pro
• With Dual Sim
• Sim1 = primary = business
• Sim2 = secondary = personal
• And I want to add Apple Watch SE. My provider offers the "one number" service, where my watch could work autonomously with the same number as my SIM2, even simultaneously when both are stand-by.

Question:

Since iPhone12 is "dual sim dual standby" I understand that I can not take calls on SIM2 when SIM1 is active. But if I set SIM2 to CALL WITH WIFI, or use VoLTE ... will I be able to receive data / calls on my watch, even when SIM1 is active on my iPhone?

Thank you for your thoughts or suggestions.