I have just tried to install the official MySQL repository on a fresh Ubuntu 26.04 server VM using the following commands:
wget
https://dev.mysql.com/get/mysql-apt-config_0.8.39-1_all.deb
sudo dpkg -i mysql-apt-config_0.8.39-1_all.deb
rm mysql-apt-config_0.8.39-1_all.deb
I get the same error message as before, namely that 'ubuntu resolute is not supported by MySQL'. I think you should update the repository installation package located here:
https://dev.mysql.com/downloads/repo/apt/ . It should also support Ubuntu 26.04, just like the MySQL packages themselves. Right now it doesn't support installing the repository on Ubuntu 26.04, so there is no way for me to install the newest MySQL packages for Ubuntu 26.04.