Mobile data and SIM settings are acting up

I have:
• NOKIA 2.2 Dual SIM, 16GB+2GB ,
• two SIM cards inside; SIM1 for voice and text, SIM2 for data.
(both can do all three, but these are my intentions)

I want to:
• Set it so it never switches data to SIM1 and never switches voice or text to SIM2.
• Be able to turn off SIM2 whenever I'm on my home WiFi, so that SIM2 remains dedicated to data when I turn WiFi off and SIM2 on.

What it does instead:
• Whenever I turn off SIM2, it switches data to SIM1 - and when I turn SIM2 back on, data doesn't revert back to SIM2.
• BUT when I turn off SIM1, it switches both voice and text to SIM2 - and when I turn SIM 1 back on, both voice and text revert back to SIM1.
(it only "remembers" voice and text settings, but always "forgets" data settings)

What I tried and it didn't work:
• Go to Settings > Network and Internet > Data Usage and under "SIM1", turn off "Mobile data".
(this should disable any and all "data" going through SIM1, but somehow doesn't)
• Go to Settings > Network and internet > Data Usage and under "Mobile", turn off "Temporary Data service".
(this is supposed to disable the very specific phenomenon that I'm experiencing - but somehow doesn't)
• Contact NOKIA support in their NOKIA My Phone app
(that is an entire process and problem on its own...)

EDIT 1:
The reason why I assume that there must be a solution is that my previous phone used to remember these settings and automatically did everything in the "I want to"-segment of this post.
(my previous phone:
Motorola Moto G4 Dual SIM, 16GB + 2GB, with Android 7.0)

— modified on Nov 25, 2019, 1:40:53 PM