Follow the guide below to reset your touchscreen controls, to their default setting. This can be useful if you’re experiencing control issues on bedrock edition.
Open Minecraft and select ‘Settings’
Scroll to the bottom and select ‘Default Settings’
Check to see if your issue is fixed.
If the above options don’t work, make a post on r/MinecraftHelp and one of us will guide you through some more troubleshooting.