Hi @katlegoalex
Some things to try to resolve the problem:
[https://www.hardreset.info/devices/huawei/huawei-y6-2018/wipe-cache/|Wipe the cache partition] and check if the phone now works better.
Start the phone in [https://safemodewiki.com/how-to-enable-safe-mode-on-huawei-y6-2018/|safe mode] and check.
If it works OK in safe mode then a ''downloaded app'' may be the cause of the problem. The trouble is to find out which one. You will need to uninstall each ''downloaded app'' one by one and test the phone in normal mode between each uninstall to see if it works OK or not. When it does then the last ''downloaded app'' that was uninstalled was the culprit. A ''downloaded app'' is one that you downloaded and installed on the phone and isn't one that was already installed on the phone when you first got it.