Question: how to make signum(variable) always return 1? _Envsignum0 does not seem to do it

I have not used _Envsignum0 before. Been looking at it, and I am little confused.

My testcase is the following

restart;

_Envsignum0:=1;
fy:=1/2*(a^2/y^2+2*a*b/y-4*a*c/y+b^2-4*b*c+4*c^2+2*a)^(1/2);
limit(diff(y*fy,y),y = 0,right) assuming real;

It still has signum there., I assumed all are real.

Is there a setting that will automatically convert all signum to 1?  as _Envsignum0:=1; does not seem to do it. Or do I have to explicitly add positive each time? as in

restart;
_Envsignum0:=1;
fy:=1/2*(a^2/y^2+2*a*b/y-4*a*c/y+b^2-4*b*c+4*c^2+2*a)^(1/2);
limit(diff(y*fy,y),y = 0,right) assuming real,positive;

The problem with adding assuming real,positive is that it applies to all variables in the expression. I only wanted those that has signum on them, to be replaced by 1.

Maple 2022.2 windows 10