you are wrong I’m sorry. Support for NC 26 is planned for 2024-03 which is 1.5 years after PHP 7.4 end of security support. Running “production server” connected to the internet using software lacking security patches for many months is the real problem… you can follow details in this thread On the roadmap: deprecation of PHP 7.4 but the fact is Nextcloud supports PHP7.4 way too long… they should have stopped support with NC25 to align with stopped end of security support by the end of Nov 2022…
But if you want to you can keep using NC25 with PHP 7.4 until 2023-10 which gives you more than enough time to upgrade to the next Debian version…
the issue will repeat in a year or two as support for PHP 8.1 ends in 1 year, 6 months (25 Nov 2024) but hopefully till the there will be a better solution for Debian users then…