Two luminous points disappearing in the sky

I think James K is right, it might have been airplanes. It happened to me a few times that I saw one very bright yellowish and even brighter getting dot kind of in front of me, and as it came close enough I recognized it's blinking and an airplane. When airplanes are far enough and about in front of you, there is no blinking and they look like big yellowish dots and you might even think it's a meteor flying towards you. And you saw even two airplanes flying towards you. It's possible that they look like disappearing when they turn before coming close enough.

Edit 1: @JohnHoltz correctly pointed out two errors - geosats are on the equator, not ecliptic. My brain was thinking "equator" but my fingers had other plans. I read about geosat flares quite some time ago and thought it was solstices when they could be seen but it's around equinoxes, not solstices. I've changed my mind and think planes are the most likely answer as to what was seen. However, I do stand by the statement that geosat flares end due to the Earth's shadow. They are unlike other sat flares in this regard according to CalSky which I've always trusted above all other sources for info like this. The link is in the first sentence of my original post below. End of edit.

Edit 2: (by @uhoh) answers to How bright are geostationary satellites due to reflected sunlight? explain that flares from GEO can be bright enough to be visible, and when you look at how big those "mirrors" are it's not hard to imagine!

The heat radiators are dark in thermal IR but mirror-like in the visible to prevent absorbing heat from sunlight. The solar panels are larger but have fairly low reflectivity.

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I'm 90% sure that you saw geostationary satellites catching the Sun just right causing a flare. It's the right time of the year for them to be seen, too. Jupiter is sitting on the ecliptic at the moment which is where geosats are parked in clusters (the reason there were two dots visible at 1-2 degrees in separation). Their brightness increased because they were moving towards opposition (reflecting more sunlight), then faded because of the Earth's shadow exactly as you thought. Geosats move slowly against the background stars since their job is to remain over the same point on the Earth; this is how people can get satellite TV with satellite dishes on their rooftops pointing at the same spot all the time. It'd be hard to notice their motion without keeping a steady eye on them for 15 mins or so.

Your description matches perfectly with a geosat flare and I'm a bit jealous because I haven't caught one yet! Congratulations, you witnessed an event that isn't often visible to the naked eye! They show up in my astropics all the time, but I have yet to see one with only my eyes.

A comment on the video in the link: Geosats stay in the same position over the Earth but this video makes them appear to be moving left as the stars set behind them. I was puzzled by this until I realized the ground objects visible in the bottom of the video are slowly moving, so the time lapse video was made with a camera slowly panning the to the right. The video shows the clusters well but with the wide angle the individual geosats in each cluster aren't visible. I think the ones you saw were in the same grouping.