Haven’t you thought about softer mattress. From what I see, Loom and Leaf offers very firm mattress (8.5/10) which may be uncomfortable for many people. Standard firmness is 6-6.5. From what I see in ratings Tuft and Needle mattress has great ratings, this blog even posted it on the first spot overall before other mattresses and it has 7.5 points on firmness scale meaning that it is quite firm.
About topper - I don’t really see the reason for you to use it. As for me, it is just a way to save money and revitalize your old mattress. Topper is simply a one layer of mattress foam and isn’t needed if you have a good mattress.
Anyway, the best way is to try different mattresses and which one is the best for you. Fortunately, all manufacturers offer 30-120 days return policy