Why do expressions with physical units not get simplified?

Question

I am trying to calculate precise values for certain expressions, see the image below.

The output testZPF of the function $\Delta$Fn should be a single output. I am trying to understand why Mathematica does not provide me with a single number in fully simplified units (here the dimension of the result is $[m]$), but instead prints the result in units of $c$ and $\hbar$.

Edit

For the dimensions, I tried to use UnitConvert, but get an error here. The error is very strange as the result should have indeed dimensions $[m^{-1}]$.

Edit 2

Here is the code:

\[Omega] = 
 2 Pi*Quantity[1, 
   "SpeedOfLight"]*(1/Quantity[735, "Nanometers"] - 
    1/Quantity[900, "Nanometers"])
Subscript[m, red] = Quantity[6, "AtomicMassUnit"]
Subscript[h, bar] = Quantity[1, "ReducedPlanckConstant"]

\[Del]Fn[\[Omega]_, m_] := Sqrt[Subscript[h, bar]/(\[Omega]*m)]
testZPF = \[Del]Fn[\[Omega], Subscript[m, red]]
UnitConvert[testZPF, "Meters"^(-1)]

Answer 1

Clear["Global`*"]

ω = 
  2 Pi*Quantity[1, 
    "SpeedOfLight"]*(1/Quantity[735, "Nanometers"] - 
     1/Quantity[900, "Nanometers"]);
Subscript[m, red] = Quantity[6, "AtomicMassUnit"];
Subscript[h, bar] = Quantity[1, "ReducedPlanckConstant"];

∇Fn[ω_, m_] := Sqrt[Subscript[h, bar]/(ω*m)]
testZPF = ∇Fn[ω, Subscript[m, red]]

Using the default conversion ("SIBase")

UnitConvert[testZPF]

Using other unit systems may not convert all constants

{#, UnitConvert[testZPF, #]} & /@ {"Conventional", "Imperial", 
  "Metric", "SI", "SIBase"} // Grid[#, Frame -> All] &

You can convert to any compatible unit, i.e., a distance

UnitConvert[testZPF, # <> "meters"] & /@ 
  {"centi", "milli", "micro", "nano", "pico"}

As pointed out by Domen

UnitSimplify[testZPF]