I am trying to read many manga from different years starting from the oldest and then work through them until i reach the newest.

So far, i have added theae mangos in a list:
https://anilist.co/user/Huss/mangalist/Legendary

Can't really go wrong reading one of Tezuka Osamu's and Go Nagai's works. They pioneered a lot of "modern" concepts.

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Banana Fish - 1986
Kyou kara Ore wa!! - 1988

Orochi - 1969 - an early horror manga
Fushigi na Melmo - 1969 - this one is odd but kind of cute
Versailles no Bara - 1972 - a classic historical shoujo
Souin Gyokusai seyo! - 1973 - a philosophical war manga based on the author's own experiences
Terra e... - 1976 - a classic scifi manga
Boku no Chikyuu wo Mamotte - 1987 - another classic shoujo, this one with scifi elements
Nemuranai Machi kara - 1989 - a short manga about a girl and her father
2001-ya Monogatari - 1984 - a collection of interesting scifi short stories

I've read a lot more from this era but I just listed the ones I thought were the most enjoyable/classic. If you want a specific genre I can give you more recommendations. (The oldest manga I have read is from 1957, it is Sakura Namiki).