Get your bloodwork done at least as a baseline.
What's your diet look like? What's your TDEE? How much water do you take in a day?
You did test and deca for a while, how long ago, what protocol, did you do bloods then?
We are missing a LOT of info here to be able to help fully but..
37yrs old, as loaded of a statement as this is you're probably getting lower on endogenous testosterone but I don't know your body and could be completely wrong about that, that being said, again, get your bloodwork done so you know where you are starting from. It's worth noting if you have low T levels and insurance you might be able to get TRT covered.
If you're determined to add something in, add test cyp at trt doses and see what your body does.
If things line up properly, ie there's no outstanding reason you shouldn't be losing weight or gaining mass, your diet, training, sleep, and water intake are on point and you are CONSISTENT, I think you'll find the result to be pretty pleasing.
To me, gear is frosting on the cake. GH is the cherry on top, but the foundation is all you bb.