Constantly out of space to run programs on Mac mini

Details, please?

Someone here will be happy to help you but you're going to have to give us something more to work with. Details matter.

Please see: Writing an effective Apple Support Communities question - Apple Community

When you purchase a Mac, you have a choice on how much RAM you want. How you choose will depend on the apps you are planning to use or how many apps you want to have open at the same time. Photo/Video processing apps will consume more RAM and you would want to make sure you take that into account on any purchase. The minimum amount of RAM is fine for basic email and web browsing along with the apps installed on the computer. If you purchased the minimum amount of RAM and have many apps open at the same time, you will need to manage that better to make use of the RAM you have. Very seldom is it necessary to have more than 2 apps open at the same time.

Also make sure you do not install any:

• Cleaners (such as CleanMyMac)
• Optimizers (such as apps that claim to speed up your computer or perform file maintenance)
• AntiVirus Software

if you are running low on space, you can purchase an external HDD or SSD of sufficient capacity and move your larger files (videos, pictures, documents, etc...) to it. once they are on the EHD, you can simply erase the same files from your internal drive. and, if it's just going to be used for storage, you can use an HDD and save a few bucks over the cost of an SSD. FWIW, i personally keep very little on my internal drive.

also, you may want to read this article:

Optimize storage space on your Mac - Apple Support

additionally, you want to keep ~ 20% of your local drive as free space for proper operation of macOS.