@Lafong thank you very much for the answer! Now I am hungry, I love shrimps.
I will do it like you proposed:
1st SSD: OS and all aps
2nd SSD: all data, backup of SSD1 --> I will get the Crucial MX500 (1TB or 2TB)
drive 3: daily backup of SSD2 --> maybe 1 or 2 WD Blue 2 TB in a Raid...