I do not use very high-demanding tasks.
In this scenario, as rightly pointed out by benwiggy, micro-managing your computer's battery is probably more hassle than it is worth.
However, if you do choose to go this route, using a lower wattage charger is probably not the best solution. If you mostly use your computer plugged in to AC, you could ...
A low-power charger may not have sufficient power to charge your laptop while you are using it. Even though it's plugged in, the charge level may still go down, or stay at the same level. Or it might go up, but only very slowly. If you have peripheral devices connected that use power, the problem may be worse.
Your laptop draws the power that it needs, ...
With a fast charger, you charge your Apple iPad/iPhone faster ( USB-C 18 W chargers minimum) than with a regular charger. The following models have the fast charging functionality:
iPad Pro 12.9 inches (2015 or newer)
iPad Pro 10.5 inches (2017)
iPad Pro 11 inches (2018 and 2020)
iPad Mini (2019)
iPad Air (2019)
Fast charging is enabled with USB-C Power ...
Taking the information from your previous question and from this one together, there is a high chance that the mainboard, the battery or any other critical hardware component got damaged when you "had mild water vapour damage after i inhaled steam near my laptop". This isn't something you can fix in software, so bring it to your nearest Apple Store ...