sudo results in a new session with a new controlling PTY

On Linux Ubuntu when at terminal I run sudo su or sudo su - the system creates a new session with a new controlling pts, namely ubuntu@ubuntu:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 22.04.5 LTS Release: 22.04 Codename: jammy ubuntu@ubuntu:~$ ubuntu@ubuntu:~$ uname -a Linux ubuntu 5.15.0-124-generic #134-Ubuntu SMP Fri Sep 27 20:20:17 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux ubuntu@ubuntu:~$ ubuntu@ubuntu:~$ ps PID TTY TIME CMD 143254 pts/0 00:00:00 bash 143302 pts/0 00:00:00 ps ubuntu@ubuntu:~$ ubuntu@ubuntu:~$ sudo su - root@ubuntu:~# root@ubuntu:~# ps PID TTY TIME CMD 143304 pts/1 00:00:00 sudo 143305 pts/1 00:00:00 su 143306 pts/1 00:00:00 bash 143316 pts/1 00:00:00 ps root@ubuntu:~# Is it an expected behavior? As requested in the comments:

$ ps     
PID TTY          TIME CMD  
146202 pts/0    00:00:00 bash  
146231 pts/0    00:00:00 ps 

$ sudo -s 
root@ubuntu:/home/ubuntu# ps
PID TTY          TIME CMD  
146233 pts/1    00:00:00 sudo  
146234 pts/1    00:00:00 bash  
146240 pts/1    00:00:00 ps