I'll be the first one to say it: I know what you mean when you say "back up all of my files," but a RAID isn't a backup. It will guard against a single drive failing and allow you to keep accessing your data, but it can't guard against the data being corrupted or deleted by some other means, and it shifts the single point of failure to the RAID controller. Although you could always run two RAIDs to guard against that... (no, don't do that.)
You have a few options. You talk about "enclosures" in your post, but mention RAID devices in the subject heading. You could buy dumb enclosures and use macOS to handle a software RAID, but I've tried that in the past and found it to be pretty clunky and unreliable.
I use a Drobo 5C. It was dead-easy to setup and use, and the entire process reminded me of the experience with setting up and using Apple products, even down to the unpacking process. I have a Synology router (purchased after the 5C) and it makes me think that if I ever need another "direct-attached storage" unit, or if I need to add a "network-attached storage" unit (DAS and NAS), I might go with Synology over Drobo. The Synology systems are like mini-computers of their own and can do some things that the Drobo can't. The downside is that the software, at least for their routers, isn't entirely glitch-free. I've had more than a few episodes where things that should be working and functioning aren't, and it's frustrating. To be fair to Synology, their router line is newer and their storage units are their core business, so I'd expect the storage lineup to be a bit more polished.
Drive manufacturer and model... no recommendations. You can try to look on BackBlaze's reports to look at failure rates for various drives (manufacturers and drive size); most people seem to swear by or swear off of a certain brand based on their experiences, but in general most drives are fine today. I have four Western Digital Red drives in my Drobo, and one Western Digital Green (an old drive, brought out of retirement). Performance is fine, noise levels are fine and usually near-silent even with the whole unit just a little more than arm's length away from me. I have been eying the Seagate "Iron Wolf" line (similar to WD Red - optimized for DAS/NAS units) for possible size expansion, but would go with WD Red if they were cheaper.
Speaking of backups, I use BackBlaze to back up my entire system and Drobo. Unlike most online backup services they don't have a storage limit. Their price is competitive, they have a native Mac application, there's an option to encrypt with a personal key, and if you need your data quickly but don't have a good connection to get it, they offer to load your data onto a hard drive(s) and mail them to you. There's great peace of mind in knowing that even if my house were to go up in flames, or if someone knocked over my Drobo, my data would still be safe. If you're interested, send me a message and I can send you a referral link, which would get both of us a free month of service.
