Hi mug and welcome to the Mattress Underground 
Sorry to hear your ikea bed sounds like it’s not working out for you any longer. I enjoyed your description of the 1" mystery latex…even for a lower bmi that’s a very thin comfort layer, and you are likely bottoming out to the layers below.
Since any mattress you choose will be based on your Stats (height, BMI, sleeping position(s) and any underlying health conditions) - thanks for providing those- and your PPP (Posture & alignment, Pressure relief, and Personal preferences), the good news is that with your lower BMI you have a lot more options in mattresses and can concentrate on the comfort level, as you should have good support with any decent, well made latex mattress. As you can see comparing the the Mattress Specifications You Need To Know to the Mattress Durability Guidelines, latex is one of the most durable materials you can have in a mattress.
Talalay and Dunlop have very different feels, with Talalay being ‘bouncirer’ (think of the difference between angel food cake and pound cake).
I looked at the Naturepedic Trilux, which has
an organic cotton & wool zippered cover, 3 3" layers of organic latex with configurable right & left side comfort levels from plush to extra firm, and they state they can ‘swap layers for free’ even years later. The Saavy Rest Serenity also has 3 3" layers of latex and configurable split layers with your choice of Talalay or Dunlop,
With comfort levels of soft solid to a firm/firm split. They have a 90 day layer exchange. Both of these are well built and allow for quite a bit of customization and layer exchange but as you say, they are quite high priced, but if you find that you prefer all-latex to a hybrid with coils, with the Trilux having much longer layer exchange policies, while the Serenity allows for use of either or both Talalay and Dunlop in their layers, giving you more freedom of customization. As @NikkiTMU said, if it’s in your price range and you find the right comfort level combination, you should be fine.
You mentioned APM being quite less expensive…I will say that they have a vast amount of experience in matching sleepers to their perfect match, and as their reputation rests on each sale they do try to go above and beyond to help you find the right combination for any consumers sleep profile, as do the other Trusted Members of the site like Luma Sleep EZ Flexus and Latex Mattress Factory among others, who carry all latex and latex hybrid mattresses. purchasing online can be a ‘guess’ but they all provide great quality, excellent customer service and generous exchange and return policies…providing them your Stats, PPP, mattress history and the ‘feel’ you are looking for they
do take a lot of the ‘guesswork’ out of online mattress shopping.
Whichever option you take, please feel free to drop in and let us know how you’d new mattress feels after you spend some time with it. Hoping for many years of restful sleep for you going forward!
~ Basilio