Drupal Oliver theme usage/workflow

I work at a smaller to medium size academic library, and we've been using Drupal as the CMS for the library's website. We've used some none-core themes before but now we would like to start using the default Olivero theme with its excellent features.
This theme is part of the Drupal core now.
My main question is, what strategy or approach to use when having a customized Olivero theme and dealing with frequent Drupal core updates?

With each Drupal core update the theme will be reset to the default state (the state of the new core/theme release). What are some of the approaches and strategies to deal with this? Is there a workflow suggested on using this default theme as the website's main theme and dealing with updates? Is sub-theming the only way to go? I looked at these discussions: https://www.drupal.org/project/olivero/issues/3191809 → and https://www.drupal.org/project/olivero/issues/3143702 → but would like to compile a more complete picture of the process. I wish there were some presentations to this effect at DrupalCon conferences, but it seems like Olivero and its features are mentioned in general and never in a complete practical example... I am sure many more none-full-time-developer users would like to see this information...
I appreciate any feedback/pointers on this!