If it doesn’t even boot from the USB stick then it’s probably a hardware issue.

They are trying to make money to stay afloat. Postmarketos is a community project so it’s not comparable. And neither Purism nor Pine64 seem to be huge commercial successes just like Jolla, though they seem to be doing a bit better.

They have been owned by a Russian state-owned telecom corporation for a few years until recent events (Russia currently tries to push Sailfish OS fork as its “russian-made” mobile OS). Original Finnish management has split off to a new independent company with the same name last year, and this looks like their last ditch attempt to continue existing. I don’t expect they will last much longer (the reason why they were bought by Russia in the first place was that Jolla failed as a business).

Qt 6 has been out for more than three years now.

Gconf was text though (well XML actually but not binary).

It is scalable but the icons are still drawn against the virtual pixel grid. If an icon is designed to be perfectly pixel-aligned when rasterized at a certain size, then rasterizing it at 1.25 of that size will cause small distortions if it contains small elements (such as 1 px width lines).

Even “real” fractional scaling in Plasma with Qt 6 is not much better. Text will look slightly sharper, but icons are still blurry. There is no way for them to look sharp with 1.25 scaling since they are drawn with a pixel grid in mind. Unless you invent some way to stretch svgs so that their individual elements and spaces between them retain their integer-ness while the scale of the whole image is fractional.

The only other solution is monitors with 300+ PPI where blurriness is simply not noticeable (that’s the way Apple went).