Thanks for the information and advice.
So, this mac of mine will still be fully usable.
Regarding my new mbp that I will get in a few weeks (I guess) with monterey,
what is your opinion about the new feature of monterey about 'optimized battery charging'?
Does this help in the maintaining of the battery?
It is a beneficial feature, especially if we compare it with what we were doing in past.
I was always plugging off and in my charger, in order to maintain the battery life. That was really unefficient and weird.
Now the optimized battery feature works in a way that, it tries to understand your computer-working habits like when to charge, when to discharge, when to be away, when to run, when to shut down etc. If you are a user who works in a timely-determined manner like open the PC at 08.30, close the PC at 20.00 etc, this feature is beneficial. But if you use it whenever you need it, or undetermined, not-planned, then I suggest you to use a 3rd party solution like AlDente, which is nowadays the best software around.
For the optimized battery selection, first it has to understand your working habits. Then it can behave in a beneficial way that fits to your working-type. However I am pretty sure that it will screw it until it understands. During this time, it will keep the battery always at 100%, so this will degrade the battery day by day.
For this reason, I would suggest anyway to use either AlDente (even the free version is perfect) or Charge Limiter. I am using the paid version of the AlDente on my 2021 MBP 14" for almost 1 month, it is working excellent, however I can surely say that it not explicitly needed to obtain the paid version. Even the free version does its job perfect!