there is not such a recommendation, nowhere 
… it was one 30 years ago…
With system managed there is a formula ( exaplained it sometime in forum , e.g. ) and these let set ~8-9GIG default for 64GIG users with enought free disc space.
never disable it …
Let is on “System Managed” or set a lower manual size if you need the disc space…
You also not need magical memory clean-up tools!
And a note: If your pagefile was 22GIG, then something is/was wrong at your system/application. MSFS does not consume these amount of memory/pagefile.
By the way:
that my setting with 64GIG RAM since years ( and beside of MSFS I use realy memory intensive applications ):
And I forgot Process-Lasso… I want to remember that these tool was one of the big trouble maker while ago. It let crash MSFS… It is simple not necessary and should only used if users exactly know what they do.