The POST workaround does not work for some websites, mostly forums-type websites, wherein the search result URL does not show the text that was searched for OR if it has a random string generated in the URL along with the text, which changes with very search (kinda like a unique search ID).

Other than that, its very intuitive to use and easy to add search engines to once you create the "Searches" bookmark folder. Can't get simpler than this.

Its just for the lack of POST support that I am forced to use another extension called "ContextSearch web-ext", even though it is way more complex to set up and use than this one.

Good idea! But not getting the search engines already installed is a failure. Bookmarking each search site is too much work to get it working.
I know, Iknow, it's a limitation of the webextensions API, but perhaps you/we should talk to Mozilla developers on how to make it work and correct/patch the API.

i forgot to rename my search's folder to Searches, duh. im sure the more i use it the more ill have some suggestions. for starters, would be nice if you could use the middle click to keep the highlighted word selected and the context menu open to continue to keep running searches and opening tabs using different search sites. this is something SmartSearches could do, so this is a bit of a downgrade switching to this addon but it sure beats not having anything.

All searh engines I used are already collected in Search field. I think this extension should get search list used in browser. Making list of search engines again is not good idea.