That's a whole lot of issues
None of those would I say are nitpicks in a $70k plus vehicle. The vehicle should just WORK at that price point, especially when they're selling this "EVs have less to go wrong" business.
Official "ticket" count with Rivian is 7. They acknowledged and agreed with all of them when I dropped it off.
I don't think Rivian sells the "EV's have less to go wrong", I think EV enthusiasts say that a lot and it's become some form of understood truth that is mostly false. I still contend that all the same systems exist in an EV that exist in an ICEV. You remove an engine, multi-speed transmission, and fuel system; but then add back in a high voltage battery system. Sure, the EV has fewer moving parts, but overall part count of the vehicle is still well into the 30k range.
As far as why the loaner feels better... The logical first answer is you take worse care of it than people do loaners. This seems HIGHLY Improbable. Answer 2 is maybe the SUV is designed to be more luxurious and the truck more utilitarian? Also improbable, they're basically the same thing. Answer 3 is different years, meaning the R1S is newer and thus they had better refined their processes. As I recall, your truck was like a leftover model? This is what I think is most likely, your truck was just an earlier build with some lot rot, and the R1S is a newer build doing better.
The other option is of course that Rivian has zero quality control, and their process is totally and massively incapable of a consistent result. It's very possible, but I wouldn't jump to that conclusion based on 2 data points.
Off these two data points.....I think I just got a dud, and arguably a less than ideal configuration. My truck has ~15.5k miles and is a 30XXX vin. The loaner is a 09XXX vin, and has just over 17k miles. The loaner is a '22 R1S, quad motor, large battery with 22in "street" tires. My truck is a '24 R1T, dual motor, large battery, with 20in "All Terrain" tires. I do suspect that mine was sitting around before being sold, I'm unsure if it was "lost in the corner of the shop" or had a manufacturing issue that held it back from being released. Considering the numbers of problems, I'm betting on the manufacturing issue. Rivian made quarter end sales targets with my help, but now they get to deal with warranty issues on my side.
In terms of configuration, I think the dog style clutch for the rear motor disconnect was a poor design decision on the dual motor trucks. The quad doesn't have any of that connect/reconnect issues (mine was likely failing as well). The loaner has over 300hp MORE than mine, as well as a lighter wheel/tire package. I'm sure this masks some of the wonky suspension issues, and also contributes to the noise level. The half worn AT tires on mine are loud as dammit, I think spending 10hrs in mine on Monday, then immediately hopping into the loaner on Tuesday really illustrated how loud they are.
I'm pretty sure the loaner has the revised dampers in it as well. Mine has the original spec. Rivian updated the dampers for the Gen2 vehicles, and they are backwards compatible. This is the 3rd time I've had the loaner, and it rides SIGNIFICANTLY better now than when I had it back in November. I can't fathom the OTA updates making this marked of a change, and suspect the service center updated the dampers in the loaner. The "front clunk" issue in mine I think also contributes to the feel. I've noticed that mine had a "steering wheel shake" over square edged bumps, like expansion joints and such; the loaner doesn't do that at all. Same with the Driver assistance. Mine "jerks" when it's disengaged, the loaner has none of that. I think the alignment being off on mine is messing with things on that front.
SO.....hopefully I get some new dampers out of this, and the ride gets better. I'm considering moving to a spare set of 22in wheels, and street tires for the summer for mine for the noise reduction. I can sell the wheels when the lease is up and recoup some of that cash. Tires should last twice as long (because there are two sets now). Wheels/Tires are relatively easy to swap, and I have a spot at the office I can stash the off season units.
Ultimately, I can only complain so much. Service center continues to be SUPER communicative and easy to work with. I have a very nice loaner vehicle, and the overall impact to my life is just a little agitation, and honestly a little bit of time. I'm pretty certain that I wouldn't get this level of service from a legacy style manufacturer. I would love to compare notes with someone that loses a 6.2L in a Yukon. They're similar price point vehicles, with similar failure modes to mine.