That's totally possible - I have one medium size org that uses Grants exclusively for this purpose. We're using some simple Word Replacements -> in civicrm/admin/options/wordreplacements?reset=1 to help Staff use native CiviCRM Grants to track income:
Avada, Divi, X theme, Genesis, Virtue and in general most well-developed WordPress themes work fine. I think BeTheme is OK too.
The Slider Revolution plugin causes JS problems and can be disabled and replaced easily. A lot of commercial themes bundle this plugin.
You can still expect to do some work making CiviCRM pages display nicely because CiviCRM uses ...