One frustration of being a developer is becoming fairly opinionated on how one thinks things should work. When my family have tech issues, if they cannot figure things out in a short time, they will often accept it as-is and move on. Being a developer, I often experience an irrationally large annoyance and spend more time than I should trying to figure things out or trying to change things how I think things should work.
This extends to other places as well. Many have had the experience of finding a tool that almost does everything that they were hoping for except for a few small bits. Maybe the tool is closed source, or has no type of plugin/api, or is in a language one is unfamiliar with. If it is an open source project, sometimes you can submit a request to the maintainer and maybe they can help you out. Since they are the one most familiar with the inner workings of the tool, they would often be able to implement something far faster than you can. (Often a new developer has a long ramp up before they have enough background to contribute new features.) However, most open source maintainers are people with limited time and it’s quite rude for us to expect that they will always selflessly give us their time.
Even though this tool does 90% of what you were hoping for, to get that last 10%, it feels like your only choice is to rewrite from scratch using the tools you already know.