Fix opencart server cache issue

I use opencart 3.0.2.0 and I am trying to make some changes to the theme but none of the changes reflect. 1) tried changing theme from the theme editor, [login to view URL] but nothing is reflecting onto the website. 2) tried logging into the server via putty and edit the [login to view URL] file and still no change reflecting on the site 3) tried updating the [login to view URL] for some border removal. not reflecting on the site. I already tried clearing the cache on the linux server, on the opencart admin module right top gear for theme and sass. No fix. Restarted apache thrice. no fix. I am sure this is a very minor fix I am missing, can you help me? I am guessing this is a quick fix for an expert. Lowest bid will be accepted. One of many projects to start with. Will use services repeatedly if good.