Is it practical to have the unit recharged, or is this cost
this unit cannot be "recharged" in the same sense as recharging your car or home A/C
like a window A/C unit, it does not have ports to screw on a set of charging hoses
generally speaking, low freon is not a problem with a dehumidifier, they are not prone to leaking refrigerant
problem is more likely a dirty or mashed condenser or evaporator coil, or a defective thermostatic switch, or other issue, not low refrigerant
And, if fixed, will it last?
if it did have a leak, and you did weld on a charging port and evacuate/recharge, it would only "last" if you also fix the source of the leak
generally speaking, a dehumidifier that is leaking refrigerant is very rare, and also not worth the hassle of repairing and recharging, for most people.
but I believe your problem lies elsewhere, as noted above, which ~would~ be worth fixing, and that fix will "last"