Real pedal steel sounds are basically impossible to emulate. Heck, even most steel guitarists don't do so well.

The key thing isn't the slide or the volume pedal - it's
changing chords by moving one (or more) notes while others stay still. For example, play a G and D note together. That implies a G chord. Now bend the G up to A, and you get A and D, implying a D chord, a I-V harmonic movement. Better yet, bend thirds - C-E to C-F, for example. Now, play four notes at once and do the same trick. THAT is why the pedal steel sounds so amazing! That's also why it's a difficult instrument - you really need to know your chords and voice leading inside and out in order to play it.
Lap steel can get you some of the whine, but not the harmonic motion. Guitar with a volume pedal... ehh. There's a whole subset of country guitar playing that's about getting pedal steel licks on a regular guitar using oblique bends, which is a fun art form itself if you keep in mind that it's just a shadow of the real thing. There's a device called a B Bender that's sometimes fitted to Telecasters (and occasionally other guitars). It'll bend the B string to C#, or perhaps the G to A, and it sounds a bit more like pedal steel than oblique bends do. The song "Take It Easy" by the Eagles uses a B-Bender for the lead guitar, and that's pretty characteristic.
Once a month or so, I sit down behind the pedal steel and let it kick my ass. The only way to play it decently is to practice every day for a couple of years, assuming you're already a competent musician when you start. Hardest instrument I've ever tried! Forget imitating it on other instruments at anything above the parody level!
You want some "country" pedal steel on your recording? Here's my advice... find a nice sample library of typical pedal steel licks, and use that. Or hire a session musician.