Hi Jaceinwinter.
Welcome to our Mattress Forum. 
Sorry to hear you’re having trouble finding a comfortable, soft, supportive mattress. What is the current brand of mattress you are sleeping on? What material is in the comfort layer? Are you a side, back, stomach, or combo sleeper?
You’re not the first person in the forum to have this dilemma. You may find this thread interesting as well as this one. I also found this thread and this one. I hope some insights are available in any of these threads.
The softest ILD you can get from latex is 12. For memory foam, the softest is a 10 - 12 IFD. Are there any deal breakers when it comes to your mattress? Any additional must-haves beyond adequate “sinkage?”
Thanks for answering my 20 questions.
NikkiTMU