I wouldn’t recommend Synology either because of them constantly removing features, adding limitations regarding the HDDs you need to run and the fact that it’s not even a “regular Linux” distro running on it.
Hence spending so much time fighting against the system or just doing it “their way” is very annoying.
I had one myself but it’s really annoying from a perspective of a tinkerer. Might be fine for the average person that wants a plug&forget solution.
Best would indeed be to have your own DIY TrueNAS or alike yes but if you’re not feeling comfortable doing so, I guess you can always try some of those:
Depending on your budget and needs, there are plenty more in the same ballpark if you check a few reddits.
I also saw that Ubiquiti released their solution. Not sure if you have some gear from them or do enjoy their ecosystem as a whole maybe?
Honestly, asking which off-the shelf brand to put your eggs into is quite a political question in itself because all the wrappers are bad in their own ways, but they make the basics simple if you are fine using their apps?
Any would do the job I think, it’s more about what you care, want and wish to do/have once setup. 