I thought Lucid made a big HW upgrade (at least on the computing side) in 25 model year?I'm with you. Although we are in the minority, I didn't hear too much difference during my three month trial. I listen mainly to podcasts too, and used Sirius for a couple years listening to sports, rock and jazz. I would describe the sound as neutral and accurate.
Even though I have DDPro, I rarely use highway assist. The roads here are too congested and early experiences and my OCD prevent me from enjoying the ride unless I'm driving. However, as others pointed out, the 360 cameras are worth the upgrade.
What year is the car you are considering? My '23 Touring does have the hardware for both DDPro and SSPro so I could pay to activate SSPro at anytime. You maybe lucky....
About OP's question: DD Pro is very useful if you do lots of highway driving. I don't do a whole lot of highway driving on this, but every time I do these days, it works great.
I don't have SS Pro. In my opinion, the base version is not something that should be on an $80K+ car. I've had better ones on $40K cars. I've seen in this forum people complaining about SS Pro as well (although the feedback seems to be more positive recently) - but I guess it is definitely better than the base version.