Help me make my mattress safe, pls!

[npl]

Expecting a little one in a couple of months, and preparing to co-sleep again, but I have a new bed since the last was a newborn. I'm trying to figure out how to make it safe for the baby.
I have a mattress with a euro-top, which is nice and soft on top, with firm springs for support. Currently, I have a quilted mattress protector for slight spills, etc, which I plan to remove. All together, it's very cushy, almost like sleeping on top of a thin comforter!
I know that setup isn't safe for a baby. I'm trying to figure out how to make the mattress safer for a newborn, without having to either buy a new mattress or lose all the cushioning, which I need for joint pains.
I'm planning on having a bassinette or side-carred crib next to my bed, but I know from experience that baby will end up spending a lot of the night right next to me, or in my arms.
Any advice on fixes, and ways to assess if I've found a safe solution?
TIA!

[Katie T]

Im not familiar with that kind of a bed, and dont have any advise on making it safer, but we have a xtra firm bed with a pillow top on it and although I know it isnt recommeded for cosleeping using a pillow top its not that squishy so we have threw 2 kids and have had no problems. I keep the little ones on there backs to sleep and I dont think it is such a problem for them (sleeping on a pillow top) once they can roll over by themselves.
Happy cosleeping

[npl]

Thanks for the feedback!
I had a really plain and simple bed for the other 3 kids, so I'm really not sure what to expect. DH pointed out that I could always move one of the guest beds up to the nursery and sleep with the baby in there, but that's just a twin, and it seems better to make the double/full sized bed work.
I'm wondering if anyone has any suggestions of something I can use on top of the mattress that would even out the quilting a little and make a firmer, flatter surface?