For home projects I would grab a student level set with at least a dozen colors so you can mix without getting muddy... A medium viscosity paint is easier to control than thick paste for a first go and still gives strong color on wood, card, or canvas board. No fuss.
Drying control is mostly about habits. Squeeze tiny amounts and add a little water as you blend, and keep your mixes away from moving air such as fans or open windows.
A local battery shop can rebuild your pack with quality cells while reusing your case and electronics but then, if you want to avoid the marketplace gamble. cost is often similar to a decent aftermarket and you keep the original fit and safety parts but then... not for everyone, but it works... Otherwise stick to an exact voltage and connector match, choose a modest capacity increase, and favor a seller with documented support and a real warranty period. Store at partial charge if unused for weeks and avoid charging right after a hot run. Your daily dog cleanup should feel normal again.
