ごった煮 is just "hotchpotch" or "mishmash" as jisho.org says, but you've misunderstood the first three sentences. This -もの is not 者 ("person"), but a kind of suffix that attaches to a noun and forms a genre name. It can also refer to works in the genre. もの is also commonly written in katakana and in kanji (物).
- SF物
works of science fiction
- 日常モノのアニメ
slice of life anime
- 悪役令嬢もの
novel featuring the villainess-as-a-heroine trope (somehow it's popular these days in Japan)
- ループもの
time loop story/genre
- 勘違い恋愛モノ
I-am-being-mistakenly-loved-by-someone sort of story/genre (e.g., a commoner heroine loved by a prince who believes she is a princess)
So the whole passage is:
悪役令嬢ものです。ループものです。勘違い恋愛ものです。ごった煮です。
This novel is in the 悪役令嬢 genre. It's (also) in the タイムループ gene and the 勘違い恋愛 genre. It's a hotchpotch (belonging to these three genres).
Text like this usually appears in a preface or a review. If it's really said in a monologue by a heroine herself, think of it as a "breaking the fourth wall" sort of joke.