I am not entirely sure how, but it seems all 10.2 instances that I have access to, have the same information in their "my,cnf":

'# you can't just change log file size, requires special procedure
#innodb_log_file_size = 50M

This claim is not correct, right?
I have several times changed the size of my instances onnodb_log_file_size, by simply stopping instance, changing this exact parameter and then starting instance again. It handles the change perfectly.
Without even changing the "SET GLOBAL innodb_fast_shutdown = 0" that is also mentioned "out in the wild", when you try to research how to do it right.

If this claim is put into any new installation, it should/ought to be right. Right
(And I find the same claim in e.g. the file [10.2.21-SourceTarball-filename]/debian/additions/my.cnf - but as I said, I'm not 112% sure this is the file I see on my instances.)

( No, I haven't tried installing it fresh on any new server to see, sorry )