Answer to: What is free available libraries, packages or sdks out their to take 10m resolution imagery from sentinel 2 down to 5m resolution

Just about any image upscaling tool should be able to do the job, no? You're trying to upscale the image going from a 10 by 10 meter square per pixel, to a 5 by 5 meter square per pixel. You can simply interpolate the pixels (resampling the image) to a different resolution, GDAL and the Python API or gdalwarp CLI tool can do this, if you want a visual tool QGIS or ArcGIS can both it as well. Otherwise, as you mentioned, using ML based super-resolution tools like Sen2Res. But, both of those don't actually reveal any more detail, it just makes the image (slightly) less blotchy. If you actually need higher resolution detail, you'll have to pay for higher resolution images. There are multiple vendors that have 30cm or higher resolution imagery, from a quick DuckDuckGo search including but not limited to: European Space Imaging, Maxar and Airbus.