So here is what's going on.

Car idling, warmed up and ready to pull out of the garage, foot on brake and puts car into reverse, you feel the car shift and engage rough but other than that no issues when moving. Back all the way up, put the car in drive, and you feel the whole car shift forward like the car is engaging. Just saying, I'm not the most mechanically knowledged person, so I apologize if lack of me knowing what I'm talking about shows lol.
When putting into drive or putting into reverse the car feels like it sets in, kinda like putting your shoe on, and then setting in is like putting you heel in the shoe if that makes sense.
I'll go ahead and say I have zero issue with shifting, along with driving regularly there are no issues with the transmission from what I can tell. I'll say something to note is, when first starting to drive, if I get on it a little and let go, it feels like the car goes immediately into 2nd or 3rd gear, and then me letting off immediately-ish puts it back into first gear, you can definitely feel it drop; but it might just be me being a stickler and looking for issues that aren't there. What I am assuming is my car is having issues with the "engaging" part of the transmission if that makes sense.
I've looked into if it could be the driveshaft flex plate(guibo) but forums say its mainly for vibrations when driving. I'm wondering if it could be my clutch? Bad trans oil? Worn axles is what is being said online, but all bushings look good, even the diff bushings look good too. Was wondering if it is engine mounts, but but engine doesn't shift or having "engine mount issues" when revving or when driving.

I'm doing my lower trans pan gasket later today to try and see if there are metal shavings or at least clean it up a bit to see if it changes anything, but at least shooting a shot in the dark to try and see if anyone here has had the same issue and knew a fix or if anything I haven't said could be a recommendation. Thanks ppls.

 

Sounds like a failing transmission mount to me. Other than the clunking problem, do you notice any AT shifter's small vibration at around 1800-2200 rpm?

 

I sometimes get a pretty loud thud from the driveline shifting into gear. It does sound like a dull "thhh-umb" inside the car when you select drive.

It's also intermittent. Doesn't sound as bad or shift as harshly every time. It seems to be much nicer when the car is warmed up.

This is what my car looks like underneath.


Some of the rusty door hinge sounds in this video are the bushings, but the metallic thud is from the transmission sending the driveshaft into rear end pretty hard.

My transmission mounts have been replaced about 3 years ago. Otherwise I have no idea. All I know in the short-intermediate term is that the bushings in my rear end are super sloppy and allowing quite a lot of rotation\flex within the rear end. Specifically one of the trailing arms connecting to the knuckle.

 

None whatsoever, no other issues