Double pram or Pram with second seat attachment

Any mamas with a toddler 2-3 that’s walking fine but not for long periods, what pram do you have ?

My son will be 3 on Christmas so he’s old enough to walk and for a decent amount of time and also it’s not like we will be going out much. But I was planning on getting the steelcraft strider with the second seat attachment that way I can make it a single pram if I can.

I was thinking of keeping a baby carrier in the car at all times in case we do go somewhere and if my toddler needs to sleep, newborn can go in the carrier and my hands will still be free. I will also be purchasing an attachment skateboard with the seat, I feel like he will like that. Even if I don’t get the second seat, I feel like the skateboard seat and baby carrier will suffice. Also because I don’t want to place the newborn at the bottom.

Do this sound like a good idea or am I missing something ? Just want a second opinion.