It is likely that the files will be fine for years. But they may become corrupt tomorrow.

You need multiple copies, on different types of media. And check/migrate regularly.

I don't think anyone has long term experience with qlc storage. It isn't old enough for that.

Manufacturers have most likely simulated accelerated aging using heat, and set their warranty accordingly.

Don't expect more than what the warranty promise.

There is no consumer long term digital storage solution. Except multiple copies and continuous migration to new media.

No, but I asked the owners of the website and they say that you should not give up but keep trying and also reload the page and perhaps click on some of the ads.

Consider getting a good external multibay enclosure. A DAS. Directly Attached Storage. If you share it on your local network you have a form of NAS. Network Attached Storage. You can access the contents of the DAS/NAS from any device in the network. TV, tablet, phone or other computers.

It is possible to pool all the drives to create a larger filesystem. But before you do that, especially before you consider RAID, fix the backup problem. HDDs can and will fail at any time. You can (and will) delete files by mistake. You protect against this by having more than one copy of everything. The harder to replace and the more valuable, the more copies you should have.

RAID means Redundant Array of Inexpensive Drives. It is a way to pool drives so that if one drive fail, the contents of the remaining drives in the pool still can be used to reconstruct what was on the missing drive. I don't use RAID. RAID is great for businesses that need to stay online 24/7. They still need backups. I think the most common reason for data loss is user error. You simply delete something when you thought you were doing something else. RAID provides no protection against that. Backups do.

Consider using only very large HDDs. The largest you can afford. Use old smaller drives for extra backups or get rid of them. That way you don't need as many drive bays, use less power and makes less noise. Multibay enclosures are great because they reduce the clutter of cables.

If you have two 20TB drives in an external enclosure, you can use one drive for storage and the other for backups of the first. Later, when the first DAS is full, get two DAS. One for storage and one for backups of the first.

Look up 3-2-1 backups.

You might consider buying a second hand small, low power, office PC and use it as a headless (without monitor, keyboard and mouse) server, connected to the DAS.

I only use Linux.

I do both.

I have two SSD in both my PC and my laptop. And two DAS connected to the PC and shared over wifi. One of the DAS hold my large media and backups. The other DAS is mostly used for backups.

Every time I boot my PC, or laptop, a new rsync snapshot of the full /home on the primary SSD is automatically created on the secondary SSD.

I also manually create rsync snapshots of folders on the PC/laptop primary on the primary DAS and also of folders on the primary DAS to the secondary DAS. By manually I mean automatically, but only after I trigger it by double click on a script on the desktop.

3-2-1 is a suggested default backup strategy.

3 backup copies. 2 different types of media. 1 copy stored remotely.

I use a mix of backup strategies. 8-3-3 to 1-1-0, depending on what it is I backup. For example, I have two internal SSDs on my PC. Every boot a new updated versioned rsync snapshot of the primary SSD is automatically created on the secondary SSD. Only new and modified files are actually copied. Files present in the previous snapshot are simply hardlinked. So each snapshot looks like a full copy, but takes up very little storage and is very fast to make.

In addition I have two large DAS, a small NAS, a small cloud account and various external drives and devices, some stored with relatives. They are also used for backups.

I use internal SSDs in external USB enclosures. Typically after upgrading internal SSDs.

For example I have 2TB and 4TB Crucial MX500 SATA drives and 2TB Samsung EVO 970 Plus NVMe drives in external USB enclosures.

No.

Answer to the question in the title: No.

I strongly advice against that DAS. I have an identical(?) 10 bay ICY BOX DAS. IB-3810U3.

It works perfectly fine, but is flimsy and noisy.

On the other hand, the 5 bay enclosure, IB-3805-C31, is great! Solid, robust and silent. Especially compared to the 10 bay enclosure. I assume the 5 bay Sabrent enclosure is the same.

I can have the 5 bay enclosure turned on, with idle Exos drives, in the bedroom and sleep fine. Not so with the 10 bay enclosure.

Check for Uncorrectable sector count. As long as that is zero, your reallocated sectors were reallocated without any dataloss.

Modern hdds are designed to reallocate sectors in order to "self-heal" during the warranty period. So reallocated sectors may not spell immediate disaster. Just normal and expected behavior.

If you think the hdd is going bad, avoid writing to it. Only read and rescue your data ASAP.

No. I don't think you should use USB Flash at all, except as part of daily use. For long term storage, up to a year, use a proper SSDs and/or HDDs. And check and migrate.