I’m just putting the translation here… I used DeepL to translate:
“I don’t have much free space on my Android device. I don’t know if uninstalling and then reinstalling Krita will free up a few gigabytes of data from the first installation, because when I updated to the new version, the memory space was greatly reduced…”
I did have that problem before and after I uninstalled Krita on my Android tablet, I only imported the brush bundles that I really needed and liked the most. All the other brushes I had downloaded I keep on my computer. After that, I hadn’t thought about it. 
This is my experience I wrote about on another thread:
In my case, it was the resources and the amount of installed brush presets, bundles, brush tips, patterns, etc., … I have a lot!.. I backedup the brush bundles and other resources then deleted the app data, from the apps section in the tablet’s settings, and then I reimported the brush bundles that I know I’ll use the most and the app size was then at 533 MB. And yup, it got a bit bigger when I imported more brush bundles. This was on Krita 5.1.1.
Here is the thread:
Translation:
Nel mio caso, erano le risorse e la quantità di pennelli predefiniti, pacchetti, punte di pennello, modelli, ecc. installati… Ne ho tantissimi! Ho eseguito il backup dei pacchetti di pennelli e delle altre risorse, quindi ho eliminato i dati dell’app dalla sezione app nelle impostazioni del tablet e poi ho reimportato i pacchetti di pennelli che so che userò di più e la dimensione dell’app era quindi di 533 MB. E sì, è diventata un po’ più grande quando ho importato altri pacchetti di pennelli. Questo è successo su Krita 5.1.1.
Ecco il thread: