It depends on the POH (power-on hours) more than the actual age
If you just want a compressed system image, Windows has this functionality built in. Control Panel > Backup & Restore (Windows 7). It's basic but free. It doesn't support versions or multiple images so you have to change folder names if you want to keep more than one image.
Your explantion of the problem is ambiguous.
On each disk there is a hidden PoolPart folder. In Windows explorer you must enable view > hidden folders to see it.
Everything in these folders is part of your Pool. Anything on the disks but outside these folders is 'Other'.
If you want to force files into the Pool - for example using another system which does not have Drivepool installed - you have to move them into the hidden poolpart folder. This practice is discouraged because it can confuse Drivepool or cause errors. But if you must do it follow the instructions on Drivepool website/forum.
For light workloads SSDs are more reliable and long-living than HDDs. They have no moving parts.
Prior to 2011 the trend was for GB/dollar to double very 14 months. (source mkomo.com/cost-per-gigabyte)
Post 2011 the trend is for GB/dollar to double every... 10 years maybe.
The HDD market went to shit due to mergers and price-fixing.
I mean it's 2023, it's very possible the discs are junk. I got out of optical discs a long time ago but even then it was doom and gloom for the industry. Every other month an article about a plant shutting down or a brand changing discs from a good MID to a bad MID.
If a reader supports it, I would always use DVD+R over DVD-R. It's the superior format in terms of how it handles errors etc.
People who know a little about optical media will tell you to burn slow for better burns. People who know a lot will tell you to burn at the rated speed of the disc. If you are concerned about disc quality, go one notch below the rated speed (eg 12x for a 16x disc). Burning slow - such as 4x on a 16x disc - results in inferior burns. "Burn as slow as possible" is one of those stubborn myths that never goes away, you can even see it elsewhere in this thread.
You should always verify a burn, which means read it back and compare the CRC to the image file. Good burning software can do this automatically. If your burns are verified but they don't work in the PS2, it's possible that your PS2 optical drive is going bad or just not compatible with these discs.