Carinthia - Tropen

Good value for money and sub 1kg, that's not going to be easy😅. have you thought about a hammock+tarp combo? The Superlight Tent from dd hammock will be more than 1kg not including pole, peg and guy line if you take the mesh and the outer (mosquitoes and chance of rain...) Varuste.net lists the mesh but I couldn't find the outer so you might have to shop around or just get a standard tarp. That's going to be 200€+ with pole -5 for summer use seems a bit too much. You could go for a more summer-y like the Carinthia Tropen (campaign price at varuste) not the most compact but good quality, and if you do need warmer you can always get the fleece layer.

Carinthia Def 4 and for summer the Carinthia Tropical (both can be combined for more warmth). The Def is usually available at army surplus while the tropical is more rare. In the US the US extreme cold weather sleep system might be easier obtainable.

Try Carinthia sleeping bags! They are the fuckin best but a bit expenaive

I like my Carinthia but was baffled that it does not have a baffle which to my mind makes it unsuitable for cold conditions.