A good charger on a shitty lead-acid battery only helps to briefly extend the life of a shitty lead-acid battery.
A high quality Lithium Iron Phosphate battery will last about 10 times longer and be a great battery for that whole period. It will maintain a consistently high discharge cranking voltage for quick starts at a higher rpm. That reduces the strain and wear on the starter and the whole charging system.
Flooded Lead-acid (FLA) batteries have a high-self discharge rate. That means that they drain themselves of power very quickly even when nothing is drawing power from them. Leaving FLA batteries discharged will cause severe permanent damage (sulfation). The longer a FLA battery sits without being charged, the greater the irrecoverable damage to it.
FLA scooter batteries are the worst of all because they are so small, and they don't have a lot of charge to begin with. That means they discharge more quickly and don't live as long as larger FLA batteries on bigger vehicles.
Lithium Iron Phosphate (LFP) batteries are a lot more expensive at the start, but have none of the problems of the FLA batteries. LFP have a very low self-discharge rate. They usually have a built-in battery controller for charging and protection, including automatic cutoff of vampire drain loads that would completely discharge the cells. The controller prevents damage from low voltages, and LFP batteries don't have the same chemistry that causes lead-plate sulfation. LFP batteries do NOT sulfate. Can't happen. Sulfation is due to the interaction of sulfuric acid reactions on lead plates. LFP batteries don't have sulfuric acid or lead.
LFP batteries are also lighter and more durable. They are often smaller for the same power level.
TPE YTX9A-BS LiFePO4 Battery with Smart Battery Management System model DLFP9A-BSLFP
Battery Tender LFP scooter battery
Battery Tender Jr. Charger for LFP batteries
I personally own 3 of the Battery Tender LFP batteries for scooters and the Battery Tender Jr. Charger (with a quick-connect extension cable)