The regulary version in Ubuntu software doesn't work to install!!!
so, this works for me so I'm satisfeid with this.
Are you saying that the one in the Ubuntu Repository does not work but the one you get with "sudo apt install lazarus" does ? The news it they are exactly the same. The version you get will depend on the version of Ubuntu you are using but it will not be as new as RC1. (Mind you, I thought RC2 was out anyway?).
If your downloaded file from Source Forge is lazarus-project_2.2.0RC1-0_amd64.deb then -
sudo apt install ./lazarus-project_2.2.0RC1-0_amd64.deb
Would be the correct command to install that and to resolve dependencies at the same time. Sometime, despite all the advice on
https://wiki.freepascal.org/Installing_Lazarus_on_Linux people try to use dpkg to install the downloaded deb, that will fail to resolve dependencies.
When a command fails and you wish to ask for help, showing people here just what the failed command looks like makes it a great deal easier to help. That is particularly the case with new linux users.
Davo