I’m going to be honest. I think every sentence in this post is provably wrong, and I know this because I actually looked up the intonation patterns of Esperanto and Spanish, compared it to other Romance languages, etc.
However, I want to believe you dislike Esperanto because its words and word roots basically all come from European languages. That is a valid reason to dislike Esperanto, and I don’t think you’re wrong for disliking Esperanto.
I think it’s because Esperanto uses many word roots which have a similar shape among various descendants of Latin, so people who speak those languages have an easier time intuitively understanding those words. I think this occurs for some Germanic and Slavic languages as well.
To be fair, “estar” in Spanish means “to be (something-ing, something-ed, someplace, or in a temporary state)”. That said, estas (Esperanto) and estás (Spanish) are not homophones because their stress patterns are different.
Also, I don’t think Spanish has a one-word translation for “esperanto”. “Esperanza” means “hope” in Spanish, not “one who hopes”. I think “esperador” means “one who waits”, “esperanzado” means “hopeful”, and “esperanzador” means “encouraging”.
As for me, I know enough Spanish that Esperanto doesn’t sound like Spanish to me (though I’m not a native speaker). The sounds of Esperanto and Spanish are kind of similar, but not identical. For example, the voiced stops in Spanish are fricatives a lot of the time, and /j/ can become a fricative in Spanish but not Esperanto. Also, the stress in Esperanto is completely regular and the stress in Spanish isn’t.
I’m actually kind of curious how much Spanish geneva_convenience knows. Maybe I’ve actually underestimated them, just because they made some spelling errors.
I have created many constructed languages, but most aren’t in-depth and basically only exist because I enjoy coming up with new words. I don’t have a favorite, but I like ones with interesting grammar such as Goptjaam, UNLWS, Drsk, and Fith among others. That said, I’ve gravitated more to looking at other people’s conlangs as I got older. It’s been a while since I really tried very hard to create an interesting conlang.
To be fair, many words in Esperanto can be linked to Spanish, such as the word “esperi”. However, you could argue “esperi” is influenced by the French verb “espérer” (to hope).
Italian definitely has a stronger influence on the language than Spanish, looking by word roots. However, French actually has an even stronger influence on the language by that metric.
I think the “Spanish” influence you are seeing is primarily from terms which both Spanish and Esperanto borrowed from other languages, especially Latin. It could also be from terms derived from French which you are mistaking for terms derived from Spanish due to the fact they are pronounced with 5 vowels, despite the fact that the relevant words don’t actually exist in Spanish.