I was in your shoes twenty-something years ago - I taught myself to read Chinese with little more than a dictionary at hand. I initially tried working on a Jinyong novel, but it was agonizingly slow to read even a single page of it back then... My mother advised me to try one of Ni Kuang's (Cantonese: Ngai Hong) sci-fi novels instead. Following her advice, the first full Chinese book that I read ended up being '木炭' (Charcoal) from his '衞斯理' (Wei Sili/Wai Silei) series.
Looking back at it, even that was pretty much jumping in the deep end, but still, those novels are among the easier works that I've read in Chinese. If you do check out that series, I'd advise trying the early/middle period works first - the later ones get boringly predictable.
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Everything is always the work of aliens.