Recordable blu-ray discs have a reported lifespan of hundreds of years if left untouched, but the high-capacity ones (128GB) are not especially cheap right now and I assume the writing process is slow. The drives themselves may not be easy to come by in future decades. But they are your best bet for "I want my data to outlive my grandchildren."

For the rest of us, a USB spinning rust hard drive formatted as exFAT is going to be hard to beat. You'll be able to plug this into virtually any computer made in the next few decades (modulo a USB adapter or two) and just read it. They are cheap (even allowing for the rising cost of storage), fast, and most importantly, they are easy. The data is stored magnetically, so is not susceptible to degradation just from sitting like SSDs or flash drives are.

Of course, you should not store any important data on only ONE drive. The 3-2-1 backup rule applies to archives as well: 3 copies, 2 different media, 1 off-site.

Probably depends on what “consumer-friendly” entails, how it’s stored, and the quantity of data.

If we’re talking the average tech-illiterate to literate-but-cost-and-space-constrained person, probably Blu-Ray. A burner+reader combo with a stack of dual-layer discs is probably cost-effective. High-capacity HDDs would probably be equally effective if you can guarantee that they’re stored away from accidents and mishandling, but if it requires a SATA-to-USB adapter with assembly then it might possibly be out of reach for some consumers, and any risk of damage from movement could rule it out entirely.

If we’re talking tech-savvy consumers who don’t have the IT budget of a corporation, maybe LTO-5 or LTO-6 tapes could work. Tapes themselves are very affordable and have a good shelf lifespan. Used libraries can be had for under $600. The primary issues would be finding one with an interface that works with your existing equipment and software to support tape read and write.

I've been a big fan of M-Disc BD-R.

Honestly: multiple copies of encrypted cloud storage. (Encryption just for privacy.) You need decentralized backups anyway. Alternatively, two NAS systems with some RAID variation in different locations that back up each other can be more cost-effective for large capacities.

What's long-term? I have some dvd-rs that push 20-25 years and despite the plastic getting brittle they still work. I also have some ide drives that still work without problems after 40 years. I would rather aim for 20 years and upgrade the storage device if I still need to retain the data.