Archiving for heirs

My (simple) suggestion would be to-

1) Buy an external SSD drive,

2) Export a derivative JPG image (full-size) from all your photos in the Lr-Classic catalog to the SSD drive.

Anyone that has some computer knowledge can view JPG files.

Use the SSD drive only for 'heritage' photos. Label it as "Family Photos"!

You could limit your exports to selected 4/5-star photos, or create Collections of favourite photos that you then Export.

If you want to pass on the original raw files, then Export Original + XMP sidecars, for others to possibly edit in LrC or Ps (as suggested by @Jim Wilde )

There's a utility, called the Adobe Lightroom Downloader, which is designed for this purpose, i.e. it will download all your cloud assets to a local hard drive, and it can be run by your heirs up to a year after your death (obviously they would need your Adobe ID details in order to run the Downloader, but that will still be accessible for that year even after your subscription has ended). It's also available to you to use for that same one year period should you decide to terminate your subscription for any other reason.

However, I have to say that it's currently a bit of a leaky lifeboat at best, as there are several issues that you or your heirs would have to address. Firstly, your album organisation would be lost, the Downloader can only store the downloaded images in a capture date-based folder structure. Secondly, assuming you shoot raw, the Downloader will download those raw files as the "original + XMP sidecar", which means that your heirs would only be able to see the edited versions of those images if they are able to import the originals with the XMP sidecar into a program, such as Lightroom or Lightroom Classic, which is capable of accurately interpreting and applying the XMP edits. There are now a couple of other apps which claim that they can (or will soon be able to) do that (ON1 and the new Luminar AI, though there may be others). Thirdly, I'm currently seeing some bugs (or poor design choices) in my testing which I've flagged to Adobe but so far they have not been addressed.

An alternative approach would be to export all your assets, which could be done on a per album basis to maintain the album organisation. You could have your heirs do that, it may need to keep the subscription going for a short period after your death, but it would give then some options....such as exporting firstly as jpeg (or Tiff, but that'll need a lot more local disk space) to give themselves and the rest of the family instant access to the edited images. Then if there's any interest in keeping hold of the raw images, they could additionally do the export using the "Original + Settings" to preserve the raw files with settings in an XMP sidecar file.