Best UK options to retain one iphone device + 2 phone numbers + 2 network

Hello. I'm based in the UK with an iPhone 12mini currently. I have one number through an EE SIM card that I have had for 30 years.

My employer wants me have a separate Vodafone number and data plan. I want to have just one iPhone device (preferably a new iPhone 15) + retain my existing personal number with EE + add a Vodafone eSIM with separate work number and data plan.

Q1: Can a EE SIM and a Vodafone eSIM work together on my iPhone 12mini?

if not,

Q2: Can a EE SIM and a Vodafone eSIM work together on a new iPhone 15?

if not,

Q3: Should I port my existing number to a Vodafone SIM and combine it with a Vodafone eSIM and get my employer to buy a new iPhone 15?

Thank you