1. "How many repairs under warranty":
No one can predict this...hopefully no repairs needed under warranty.
Only way to REALLY get an idea of this...is NEVER purchase a brand new computer (especially when a new model is first released). Wait at least 6-12 months (or maybe even 1-2 years AFTER a model was released)...then you can see if there are a lot of dependability issues with a specific model computer.
As an example:
* M1 Mac-Mini's were released November 2020...which is just over 3 years ago. I have not heard any issues with M1 Mac-Mini's.
* M2 Mac-Mini's were released 11 months ago. Have not heard any dependability issues with them either.
Thus purchasing an M1 or M2 Mac-Mini should be reasonably safe from manufacturing or design released issues.
2. "Length of Service":
Length of service is hard to predict...since different users have differing demands. If you were a hardcore photo or video professional...you'd probably need/want to upgrade to a newer model sooner than the average Mac User...since "time is money"...and you'd want to save time with your projects.
Assuming average user who mostly does internet browsing, email, MS Office type tasks, video chats, light-moderate photo/video projects, social media, video streaming...usually you can expect at least 3-5 years (especially if purchasing a current model Mac). I happen to still be using various Mac's that are 7-12 years old.
3. "Possible Upgrades":
With a base model M2 Mac Mini...probably zero. RAM & SSD storage space can only be upgraded at time of purchase. After purchase...RAM & SSD storage not upgradeable.
4. "Overview of dependability":
Again...probably impossible to predict.
5. Regarding nearest Apple Store being 10 hours away:
This is why Apple gives users/owners the ability to ship a computer to Apple for service/repair:
Learn how to send your Mac to Apple for service.
support.apple.com
HTH,
Nick