I actually considered trading in my AGT for an iX so I can understand what you are considering. Unfortunately, I have not been able to drive an iX as there are none available for test drives where I live so it has made my decision easier (i.e. stay with AGT) because I don't really know what I'm missing. Here are my thoughts though:
- looks - Air looks better than the iX but this is subjective
- Range - they are actually quite close in terms of real world range (435'ish for AGT and 377 for iX), and probably even closer with Touring
- Practicality - iX for me is more practical as it is easier to get in/out of and using the hatch trunk is easier to load things than the clam shell trunk in lucid. Yes, there is no useable frunk in the iX but I personally don't like going to Costco and having to walk to the front and back of the car to load what I bought. I'd rather just use EITHER the front or back. With lucid, I need to use both. The roofline of the Air is quite low such that even my young kids have hit their heads on the roof getting in. Although much better with the touring, the feet/leg room in my AGT is ok for short legs but taller people have issues with the high floor despite having lots of knee room. The rear seats in the iX is more comfortable in that regard but maybe does not apply to Touring with smaller battery pack. Also, the Air sits much closer to the ground so clearance can be an issue vs iX is obviously much higher being an SUV so usually don't have to worry about bottoming out.
- Drive - not sure as I've yet to drive the iX but I've read that it is one of the quitest cars available. The Air on the other hand is quiet but has an electric motor whirl/sound at low speeds for some reason. I think both cars handle quite sporty
- Sound system - I've come to really appreciate the Air's SSP sound system as being one of the best out there but I've also ready (not heard) that iX's B&W system is also extremely good and generally I love B&W sound system. iX has Android auto and CarPlay. Lucid just got carplay recently
- Interior quality - I think the interior quality/luxuriousness of the Air is a bit better than iX although the iX with upgraded leather is close. I personally liked the crystal pieces in the iX. Also the iX panoramic roof can be darkened electronically which is a nice feature and helpful if you live in a really sunny place.
- Driver assistance - iX is much better in this regard FOR ME because in Canada, DDP is extremely limited (i.e. all I get is adaptive cruise control, no hwy assist/steering). iX also has heads up display that is not available on Air. I thought I'd like this more but in actual fact, outside of taking trips, I find the head up display distracting in my EQS SUV and actually turn it off most of the time.
In the end, I made a decision to stay with my lucid for a few reasons - 1) I know that the car I purchased today won't be the same car in 1, 2, or 3+ years. Having owned Tesla early, I believe lucid will continually update their cars and it will evolve. I can't say the same thing with legacy automaker cars like BMW. However, with that said, I do believe that the product you get now with a legacy maker like BMW (or Benz) is ahead of lucid so the first few updates will be only to "catch up" before they pull ahead. 2) lucid is different than driving a legacy car. It is more rare and the idea behind buying a lucid vs legacy car is different in wanting to be different and an early adopter of up and coming tech. It also means going through growing pains
These are just my personal thoughts having gone through the same consideration as you with the exception of owning the AGT while comtemplating the iX.