I don’t think that’s possible, at least not in an easy way. Beside of that, even if you could remove the “/apps/” part from the URL, It would still be
…beacuase how would Nextcloud know what share / calendar it should serve without the /p/9xKxpHX52sAKVgSZ part?
For file shares there is an app called ShareRenamer, but I don’t know a way, how you can do the same thing with a calendar share. And I wouldn’t recommend it either, because, wehen you share a link, that is not password protected, your only security is the random string at the end of the URL, which shouldn’t be easy guessable.
@mkorsch
I think also you should use 301 redirect. You can use e. g. php or htaccess.
I wrote a little php redirecting script for names to urls. But it is only useful with a separate folder e. g. /link and a lot of names and urls. Send me a PM if you want get it. I use it for all my nextcloud shares because i can not notice the complicated urls in mind.