You might want to try SebaMed baby product for body, lotion, shampoo. It can be due to weather that baby's skin dry. Or you can also try baby powder lotion from Kodomo.
In hot weather you can use loose clothes or material like bamboo fiber/max kool. Also if you are using swaddle try to use the linen type of swaddle.
I link my previous post here for ur reference https://community.theasianparent.com/q/sharing-few-materialbrand-suitable-nb-if-keen-purchase-esp-first-time-mu/4483572?d=android&ct=q&share=true