• Large files I don't care if I lose (perhaps videos of popular things): NAS. Hard drives are cheap, not worry about losing it, I can download it again if needed
• Storage with frequent access and security compliance: Wasabi. $6.99 per TB per month, free egress. Compatible with S3. SOC2 and PCI compliance. I use this for work as a backup to S3 for website images.
• Files I need to store cheaply, redundantly, and access often: Backblaze B2. $6 per TB per month for storage. You can download 3x the amount of storage you have per month for free, or connect Backblaze to a CDN partner like Cloudflare for free egress through them. It's also AWS S3 compatible, so you can just the AWS SDK/CLI or tools that work with AWS S3. I use this for hosting image files for my Mastodon server. Note that Backblaze B2 also has SOC2 compliance and US region available now, so it should be as secure as Wasabi at slightly lower cost if you don't have a ton of egress.
• Cheap long term backup storage: AWS S3 Glacier. $0.0036 per GB per month (so $3.6 per TB). Upload your files to S3, and add a lifecycle rule to migrate them to glacier. Glacier is cold storage, extremely cheap and great for a redundant backup. I use this for backing up photos and other files I'm going to want to store forever.

For anything I'm hosting, multiple backups. Home NAS is usually the first backup, followed by cloud storage. So if I need something now, I can get it from my NAS. If there's a problem with my NAS, I can get it from cloud (though with a delay for Glacier)