@Aichan Your suggestion strikes me as grammatically quite awkward and way worse than using they/them.
Yes, some authors have been known to use a he neutral default, that doesn't mean it's remotely good, it's not, and plenty of authors have used they/them in literature as far back as Shakespeare's works, it's not some new thing. It's old, and it's correct.
The usage has certainly gone up in recent years but even when I was a kid, roughly 20 years ago, they was used where I live in America, plus again, in legitimate history before our all times.
It just feels awkward to you because you haven't known it as long, it'll grow familiar over time if you stop being needlessly resistant to it.
But I mean hey, I can't force you to accept language, no matter how correct it is, though it is a bit petulant to be like "the language is wrong because I don't like it". 'This person' is certainly not more suitable in the least, it's grammatically incorrect at worst, awkward at best. It's like replacing all instances of 'he' with 'that man'. Awkward.