Time machine filling hard drive
I read a similar question which is now closed. I've discovered that the time machine makes 'snapshots' on my drive that take up a lot of space. I've read that OSX will reuse this space and delete old backups. Then then the answer said 'but sometimes it doesn't.
So yesterday I decided to update my OS to the latest OS, Sequoia 15.3.1 from an older version. Checking CMD I on my 512G hard drive I found that I had about 150G available, but then it also said something about a large amount that was purgable.
The update failed telling me I needed 20G. After a while I discovered that under About This Mac, or System Information, I could check storage and I found that only 18G was free.
I then spent another couple of hours tearing my hair out trying to increase this. I deleted a 50G file and still had only 18G free. Do you see where the frustration comes in. I tried doing fresh time machine backups on the two drives I use and I rebooted as suggested online, all to no avail.
Finally I came across the suggestion to use terminal and use the tmutil command. Are typical Apple users expected to figure this out? Or does Apple expect one to hire an expert or bring the computer down to the store when this happens?
So here is my real question. How can I get the time machine to stop this nonsense. If I create and delete a file between two time machine backups, I don't care if it is gone forever.
Thank you.
MacBook Air, macOS 12.5