Increase Empty Space of Storage in My Android Device

I am using p10 lite made by Huawei. I like it since the design is very good. However, I have one disappeared point about it that its performance is getting bad when the empty space of storage is decreasing. Now, the empty space is very small and its performance is bad.

I tried to increase empty space of storage in p10 lite. First I looked for a way that moves apps using a large amount of space to SD card. I found a web page that instructed the way. However, I could find a dialog that the web page instructed. There is a sentence that some android device does not appear this dialog since the developer does not allow. This means that my android device p10 lite does not have the dialog by the developer Huawei. I was sad.

Next, I tried another way that uses a default setting. In the setting, I can change the storage option that store data in SD card not an internal device. I didn't know well what would be happened if I used this option, but I did. I expected that all app data would be moved to SD card. I checked the storage, but any data wasn't moved to SD card. It seemed that new data is stored into SD card but not old data. My problem had not been solved yet.

Next, I uninstalled apps that require a huge storage and reinstall it. I expected that data for the apps would be stored into SD card not an internal storage. I didn't recognize whether is not this way is effective. I will confirm that later.