bombero, I guess I'll write some bunk and am 15 years old... I've had similar experience as Lynnmor running lawn mowing / landscaping equipment.
BEST thing I've found is to run equipment regularly (don't let is sit longer than a month). For long term storage, drain the fuel tank and run the equipment to use the fuel left in the carb. Sure, go ahead and use additives all you want, just be careful depending on them.
If you really want dependable long term storage for equipment while keeping it fueled up, try something like Tool Fuel (or Tru Fuel, might be the same company). We use it in the fire department for gas powered equipment we don't use often. Guaranteed for a minimum of 2 years in a motors' fuel tank, vented or not, and will not damage equipment in any way. Guaranteed for a minimum of 10 years in a fuel can that has been opened but then closed tightly, and guaranteed for 100 years / life in a fuel can that has never been opened and is sealed.
It can be expensive....
https://www.amazon.com/TruFuel-4-Cycle-Ethanol-Free-Outdoor-Equipment/dp/B009QT1KLO/ref=asc_df_B009QT1KLO/?tag=hyprod-20&linkCode=df0&hvadid=241895017383&hvpos=1o3&hvnetw=g&hvrand=9841800239389249410&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003336&hvtargid=pla-442590708188&psc=1