First time with a NAS, I had a fear if I would be able to work with it...
Eventually, it wasn't something difficult even for a beginner.
It was installed on an iMac.
There are videos on the internet and in Greek that gave me an idea of the steps.
I installed the HDD (Seagate Ironwolf Pro 4TB HDD 3.5" SATA III 7200rpm with 256MB Cache for NAS) and another identical 6tb (I haven't received it yet).

Update: I received the hard drive with the 6tb, which came with careless packaging, a plastic piece was broken, probably from a fall during transportation.
I plugged it in and it read normally, but the disk was scratching and making a noise like old modems used to.
It was immediately replaced by the store.
The new one that arrived with proper packaging works silently.
In addition, 8gb of RAM was also installed (Crucial 8GB DDR4 RAM with a speed of 2666), reaching a total of 10gb.
What impressed me is that it is completely silent, despite reading conflicting reviews.
By default, it is set to the "silent" setting.
Technically, as a new user, I cannot have an opinion, but if someone thinks it is difficult, they should change their mind.
I will soon test it for sharing photos and movies with other devices and I will come back with feedback.

I come from the Mybooklive 2T 2011 model (tivmobili for movies and transmission for torrents), which burned out and decided to purchase as I wanted to try something better and also with 2 Slots for Raid. I was lucky because I almost bought the previous model DS220+ (reliable and with many reviews) but I found it (with 10-day delivery) for €347, I also added a €34 warranty extension for 4 years, added on top 2 x 4TB Seagate Ironwolf Pro 4TB HDD Hard Drive 3.5" SATA III 7200rpm with 256MB Cache for NAS (5 years warranty) and Crucial 4GB DDR4 RAM with 2666 Speed for Laptop. After upgrading the RAM, object recognition was activated in Synology Photo, which runs quite fast, easily grouping the photos (~80,000) and now I can view them on my mobile with the corresponding application. They recommended me to also get a UPS, but I'm still considering it. Transfer from and to the PC is very fast with the 2 hard drives. I don't know if I connect 2 LANs and merge the two networks if the network speed will increase even more or if it's just for redundancy. If I figure it out, I will come back.

The operating system is incredible, many applications, I installed transmission for downloads, plex (I still have some issues but I think it's something in the settings), emby and the video station (surprisingly, even though it's simpler, it has no issues even with 4k ~25GB on the TV) for movies, and bazarr for Subs. Easy backup and synchronization for whatever you need. And to avoid worrying again about losing my files and photos, RAID with two hard drives. From time to time, I also backup to the USB HDD that is permanently connected to it, and I have set up a schedule to synchronize every week.

I was impressed with how easy it is to set up a home surveillance station with the corresponding application, as even a simple mobile phone can be turned into an IP camera and you can have a view of what's happening in your space, with motion detection and many other features. Every day I discover new things that are easy to configure, and there is also endless information on YouTube/the internet. I'm not an expert, but I understood that Synology's operating system is considered top-notch. In Mybooklive, I had to become an expert in Linux to be able to do simple things.

In conclusion, for home use, it is excellent, which is logical because it is also intended for small businesses.