Hi Oihana;
My latest STD framework for PB2019 MR2170 now tracks application performance, memory space and device usage. If you download the example "OrderEntry" demo APP, and run it on your mobile devices, you can use that to record the actual impact on each type of mobile device. The App, DWO and NVUO stats are logged and a performance file is generated as well. The performance file can then be graghed in the three DWO's I supply in the framework.
Hopefully, that might give you an idea of any issues it encounters that might be similar to yours. If not, then the source of the memory consumption could be your App. This could be a quick way of testing AWS as to whether its related to this execution shell.
FYI: http://chrispollach.blogspot.com/2020/04/std-web-service-framework-2020r1.html
Food for thought
Regards ... Chris
PS: The latest "Beta" version of the framework (and demo OrderEntry App) also available for download is for PB2019 R2 MR2328.