Minimal soundproofing calls for deadening opposing surfaces. Floor, North Wall and West Wall for example. That will do an amazing job of killing the worst echoes. It will still be a “live” room, but it won’t have that Kitchen or Bathroom sound.
There are methods of cheaply sound proofing tiny locations, but your job description calls for a “studio,” not a box you stick your head into.
You can do very well with Furniture Moving Pads.
You can do that with plastic pipes, too.
This is the plan for a kitchen table sound studio. Modest size is relatively easy. Trying to soundproof a room can be challenging.
https://forum.audacityteam.org/t/too-compressed-rejection/52825/22