Need a solution after the app stopped working on my phone

I have an old redmi note 10. It's old, but was more than enough for my needs until today
For the last years, it was working fine with minimed mobile with only a message telling me that the connection to medtronic's server was impossible. I just dismissed it. I only needed the app to monitor my last day of data (instead of the few hours from the pump's interface) and access my level without checking the pump, so this wasn't a problem.

But today, the apps stopped working giving me the message about incompatible android version.
Funny details being that medtronic's own customer service had told me that with the end of android 11 support, I would just loose all online function after the 15 of February. Well, it look like they were wrong.
I tried downgrading to an older version, but as it won't connect to their online server, I cannot start the older app.

I don't like the idea of replacing a smartphone that is still in pristine state, without a single scratch, and more powerful than what I need, but seems like I won't have the choice.

According to medtronic's website, only smartphone in a range of 800€ and more are available, with the Samsung S25. But I've seen people talk about non-listed phone that just give an error message saying the apps is not guaranteed to work before effectively working.

What is the cheapest smartphone compatible with this damn app ?
I'm speaking about smartphone that can still be bought new.

Alternatively, would you know of a way to make older version of minimed work again ?