A software update is required to connect to iPad - Update failed - not found

iPad 4?

That iPad was discontinued 11 years ago. I don't know if this is the issue but it is quite conceivable that Apple may have pulled the update from their web site, or at least not have one that could be applied to your Sequoia Mac.

Probably a glitch with the server. I would wait a while and try again.

Also, nothing to do with an actual iPad 4 (4th Generation with Retina Display). That's just the identifier in Finder as in there have been 3 other iPads before it named iPad, not its generation. So unfortunately Limnos answer is not relevant to this.

If you don’t have four devices with the same “iPad” name, that “iPad (4)” name can be indicative of a network error; a loop or misconfiguration in the local network.

If there is a network configuration error, that can cause problems with downloads.