The CX50 is the first Mazda I'm considering (ever). I've always heard great things, but please correct me on the below in case I'm wrong:
1) There is a spare tire on the CX50 and that it doesn't use run flats
2) Sadly, the rear suspension is a torsion beam (from the CX30?)
3) Corrosion resistance on Mazdas is massively improved these days.
4) The CX50 *should* be on the quieter side (wind noise/road noise) despite it being the 'off road' version
5) Seat comfort should be pretty good?
I am in the same situation as you! I have a 2017 A8L, and need something more practical for grocery runs and such. The A8L is a limousine and it does that job well, but it is not versatile enough to be the only car in the household. It can't even carry its own replacement winter tires, when it comes time to do the seasonal switcheroo! I had previously owned a 2017 CX-5 concurrently with the Audi and found it much more practical for daily use. The A8L is also far less reliable than the CX-5.
Now, I am going back to Mazda with a 2022 CX-5. My priorities were reliability, safety, and conveniences features (like adaptive radar cruise control, lane keep assist, road sign recognition, etc.). Like you, my budget allows me to get the Signature trim with all the gizmos that the A8L has, and adds CarPlay and USB ports as a bonus.
I decided against the CX-50 for the following reasons:
1. CX-50 has too much cladding for my taste. CX-5 looks classier and has all the same capabilities as the CX-50.
2. 2022 CX-5 was refined with more comfortable seats, less NVH, improved transmission and suspension, independent rear suspension, and has a spare tire.
3. Turbo engine does not have I-Stop tech, which I hate in the A8L. Failed several times and caused damage to my A8L.
3. CX-50 is brand new, built in a new factory. CX-5 is proven reliable, continuously improved, and built in Japan.
I am very comfortable with my decision.