DY:
“Would you similarly argue that someone who learns Torah sheba’al peh from a sefer is doing something wrong since it’s only muttar because of eis la’asos Lashem heferu?”
Would you similarly argue that now that Esther married a non jew because of Eis Laasos it is now muttar (and according to you proper) to marry a non jew?
When we say Eis Laasos and something becomes temporarily muttar or even proper for that moment that is in NO WAY coming to change the Torah value system or principles.
And yes there is very much of the Torah shebaal peh Takanah that we still observe today in spite of the Eis Laasos that is why gemaras are to this day still printed without nekudos, it is said that is why the Gra wrote mostly abbreviations and more.
The Torah’s values and principles are forever and even if temporarily suspended not subject to change.
If the Rambam is declaring that one who learns and supports himself is the higher madrega and the Kesef Mishna at no point disagrees with that rather to the contrary agrees with that point of the Rambam than any other suggestion is trying to change the Torah and FALSE.