An 8GB RAM M1 iMac, about that memory.

My thought is this: since the new Apple Silicon Macs cannot be upgraded after purchase, it's important to plan forward and buy more than you think is enough. Storage can be increased with an external drive at any time. Not so with RAM.

But the other side of the coin is that the M1 is freaky fast, so that might take some of the sting out of any shortcomings you might experience. You'll just have to keep the RAM limit in mind as you use it. Keep open apps to a minimum, including browser windows. When you're using FCP, let that own the machine when you have to get something done with it.

Enjoy your new Mac.

If the computer is doing what you need, I would not obsess over what you did or did not do. Macs manage RAM very intelligently. I have only 8GB in an old MBP running Mojave and it has never been stressed for RAM. Pressure in the green and Swap Used is zero all the time.

If your pressure is yellow I would first think software. Anti-virus software and so-called "cleaning" apps can run up temp and RAM use. Chrome is a known usurper of resources including RAM and CPU cycles.

And any Apple pro app like FC is a demanding mistress. The fact that it is "working great, even with FCPX" should be affirmation that you did not poke the bear.

There are two schools of thought: if in doubt, buy less save more and if in doubt, buy more save less. I belong to the buy less save more school. FWIW, the activity monitor on the S&P indicates indicated that $200 in June would be worth $224 today. That’s a nice shade of green you can take comfort in 😁…enjoy!