Providing access to photos should be a part of a family’s digital legacy plan, just as the family should plan ahead as to how to access the financial, legal, and other digital/online accounts of any family member in case something happens.
Compared to financial and legal digital records, photos are relatively easy to deal with. You should probably assume that there will not always be tech-savvy members of the family who want to guarantee that valuable digital family photos are passed down to the next generation. Therefore the simplest solutions are the best.
For example, you could leave multiple family members with copies of the same digital archive of your photos bulk exported to high quality JPEG. If you add keywords to the most important images or at least name the files usefully, the search feature in common operating systems (Mac, Windows, iOS…) let any family member find those photos on their computer by keyword or filename. The beauty of this is that their OS will find photos by keyword even if they do not have a single photo application installed. That releases any dependency on specific software or expertise.
The other easy way to pass down your best photos is to make photo books. Again, you can order several copies of the same books and distribute them to family members. In some families, print albums are more likely to get passed down than digital files.
You could do both, gifting multiple family members with printed albums and digital archives, and assume that some copies will be cherished and kept and other copies will be neglected and lost, depending on who received them. The longer at least one copy gets preserved, the more likely somebody in the family decades from now is going to say “We found these fascinating photos of life 100 years ago by an ancestor.” You just have to get the archive past the next one or two generations that might not value them as much.
As in nature, diversity, adaptation, and numbers increase the chances of survival.