Indeed. However, Nextcloud does not yet required PHP 8.x, and NC25 will be supported until Oktober, so sufficient to upgrade to Bookworm and new PHP when Bookworm is released: Maintenance and Release Schedule · nextcloud/server Wiki · GitHub
But indeed many applications at least still show a bunch of deprecation warnings with PHP 8.2 or even earlier PHP 8.x versions. These however can be muted and do not affect operation. The other way round, PHP 8.2 complying syntax is fully backwards compatible to PHP 7, so developers of any serious PHP application are advised to add required type definitions etc to their code, for Debian users, within the hext half year.
So basically when using ordinary maintained PHP applications and having the ability to upgrade to Bookworm soon after its release, there shouldn’t be major issues staying with Debian’s native PHP version.