[Document generation tool] Improve document generation based on templates

i've been someone who builds something based on the problems / pains i felt since, i always thought "Hey if i'm facing it , there's a chance that someone else does too " . i have built a tool for document generation based on our template simply because i hated rewriting the same document 30 times for my college lab report . Built an literature review tool because i didn't know what papers i should read and why should cite a paper as a beginner to research. Planning to build an mock interview app because my communication skills are not polished enough for interviews and i'd lose jobs cuz of that but then , when i ship these apps , the initial traction fades off i see 5-6 users using it still out of like 200 users . the spike is real and i don't know whether the core functionality of the app has some flaws? nor that its conveyed properly , and as a solo developer it provides this imposter syndrome within me , that i'm not capable like the people we see in startup stories . each time i build something i'm forcing myself from not indulge in my negative thoughts . when would i know that this product is liked by my target users ? or how would i know that i'm building the right thing?