This is actually pointless. Phones are designed to have a 5 years lifespan at best (apple) and 3 years for others. After this there is no more software support = not suiteable for everyday use anymore.
Batteries in phones are also designed to last this long so you dont need to change them.
Sure you can have modified alternatives os after your phone is no longer supported but all these os lack proprietary security drivers which makes TPM and cryptographic security unusable = a lot of important functions of your phone wont work anymore, especially things related to banking apps.
If the EU wants to extend the life of mobile phones they should force manufacturers to extend the duration of the support on them in the first place.
I disagree. An old device might not be good to daily drive anymore (for security, performance, or software compatibility reasons), but as an electronic appliance they can still see some use if allowed.
I have a couple of old phones sitting around doing nothing because their batteries are shot, but I'm pretty sure I can still find uses for them if they had good batteries. The cameras, sensors, and speakers, memory, screens, and all the other things that encompass a smartphone are just sitting there unused.
The one with a Snapdragon 820 has an IR blaster, so it could be used as a remote. It also has unused storage space.
The one with a Snapdragon 845 would be good for emulating games, frankly has a better screen than my current daily driver iPhone, and has even more unused storage space.