https://pinoyscreencast.net/phones/myphone-my28s/
With an Android phone that only has 512MB of RAM and 4GB of internal storage, that's clearly a lower-end, budget-class model.
It's not a software issue, it's a hardware issue, your phone simply isn't capable to used as a daily usage phone. Lag and performance issues are not a sign of something fixable, you need to expect them as a norm.
Really, if possible stop aggravating yourself on false expectations and get a newer, better phone. There are plenty of budget class phones that come with better hardware specs, arguably 2GB of RAM and 16GB is a more acceptable baseline for a typical usage phone.