Here is link to the post that provides important overview (describes basis of inserted Li-ion battery behavior): Librem 5 various observations - #11 by gsfs. Thanks a lot @gsfs!
Therefore we need to change our behavior, I think (without expecting that new/another Linux Kernel can do unrelated miracles, as already using the very great one, the one available as of today and currently taking great care …). Therefore I’d recommend to start to charge your Librem 5 battery when its capacity between 40%−50% (and not below). In addition, we do have another very kind and important set of recommendations (post that is over three years old) here:
Correlated thread from @amarok is here: Script to Play a Battery Charge Notification or Warning - #20 by amarok. Also (as to the content related and not to the my tone of writing), please disagree with my direction of thinking (if you have better approach, but do not blame your Librem 5 that it is not coping well with the heat when its battery already discharged to 0% and needs quick recovery dose of high current): It's a burning phone - #76 by Quarnero.