So we have the classic situation here.
We have Eheim who is pretty well known as a long term success in the field of filters and they set limits on what height works best for their filters. On the other hand we have a low level, somewhat experienced hobbyist who says it doesn't matter!
Yes, we have a very classic situation here: a physics-illiterate forum yap-yap-yapper who obviously has serious issues with "Reading & Understanding 101", not even mentioning the understanding of basic physics. One that can't be bothered to even make an effort to read what's been said (!), but still willing to spend time to leave his "mark" in the thread.
Both me and other members of this forum provided a very precise, clear and easily understandable explanation of why canister filters do
have a height limitation. Moreover, a link to a fairly good article was provided, which, albeit not perfect, did a sufficiently good job explaining the same. Not even mentioning that the proper keywords were provided multiple times, which'd allow one to self-educate themselves on this matter in a matter of, say, one or two hours (five, if your basic education is American).
But no. He didn't bother to read. Instead, he "classic situationed" us: he dumped into this forum a standard-issue one liner, in which he attempted to pull a rather and lousy populist trick: pretend as if someone here is supposedly trying to argue with Eheim. When in actual reality everything we said here agrees 100% with what Eheim says. (Eheim, of all manufacturers, is usually pretty good with physics in their manuals.)
But... you know... it takes all kinds.