I would use the Pi5 and not the Pi zero option.
Pi Zero can do the job but is easily overloaded in terms of cpu use. If you live in a busy area I would use the Pi5 with the image or the package installation on top of your existing OS.
If you’re gonna install dump1090-fa / piaware on that, it’s gonna use lighttpd which is gonna conflict on port 80 (i presume that’s where the webserver runs?).
So you’ll have to reconfigure lighttpd to a different port.
You could run https://adsb.im as a script install as an alternative, as an app install it won’t conflict with port 80 (but use 8080 and some other ports).
Or if you want to do it using docker manually, take a look at https://sdr-enthusiasts.gitbook.io/ads-b
If you’re gonna use a separate RPi, i’d recommend getting a pi4, they do the job well and i haven’t had issues with micro sd-cards breaking.
Mostly counterfeit / older sd-cards are an issue. Newer micro sd-cards last a long time.