Storage full huawei p8 lite 2017?

I have massive memory problemeda my system takes about 6gb so i only have 10gb free and 7 gb apps of which i if i get the manually overrated apps just to 1.7 gb I almost have disabled any preinstalled app at least. Can I fix it with a root if so I would like to do it via twrp how can I find a suitable version? Some apps need according to play store still 300 mb memory space the download size is however only 3 mb ivh have a 128 gb sd map on which I standartfully however no apps can save how can I somehow get memory space permanently enter the annoying fade (not wegklickbar) that I have too little memory space and I should use the tolen cleaner of huawei who also brings only about 10 mb, what can I do?

From Android 5.0, there's the possibility to set up the SD card as an internal storage partition, how can I not tell you but in google just because you will find a guide how you set up and the apps consume even more data if you have installed them so can from eg 300MB fast times 1GB are through memory data or synonymous with WhatsApp through pictures and videos you receive