Naps for younger sibling

[SquedgieBeckenheim]

DD2 is 4 months old, DD1 is 3.
We want to still keep DD2 in the same room as us when she sleeps due to SIDS risk and the fact she has congenital heart problems so we're more anxious about her any way! However, when she naps during the day she is always woken by DD1 or the dog. This happens even if she's sleeping in the sling. DD1 does not nap, so can't try to get them to sleep at the same time.
How have other people overcome this? Am I just going to have to put her in her room to sleep despite the SIDS risk? We do have a movement sensor monitor we can put on her cot.
At night she sleeps in a co-sleeper attached to my bed.

How about naps in the bouncy chair? Or a Moses basket in the corner of the room?

That's what we do. But she gets woken every time by the dog or her sister. They're loud!

Ask the dog and sister to be quiet? Do quiet activities with the sister like colouring etc. Put dog outside or in another room.

They're loud!

All the better!

Teaching a baby to sleep through anything can only be a good thing.

In a bouncy chair, perpetual movements (with dummy inserts as needed) allows for keeping baby in a deep sleep if roused slightly into a lighter sleep (and so at risk of waking up).

I had bouncer at my feet as I sat on the sofa, perpetually bouncing if baby looks like stirring. Then there would be the tv on (never switched down for the benefit of baby) and our dog sniffing around and multiple children actively playing around baby. These are good things for baby, not bad.

If baby is a light sleeper, making it silent is only going yo make that worse.