Is Flying Monkey 5e dnd overpowered Familiar?

Cool and thematic, a dnd 5e flying monkey familiar is excellent. You wouldn’t have nerfed climb and fly speeds. It would be more fun just to let the familiar be the best. An extraordinary familiar doesn’t destabilize play and can often provide a lot of enjoyment for interested players. To make up the difference in power, I would allow another non-familiar penalty for nerfing.
Suppose you make an ad-hoc change to a class’s power in older editions (i.e., you charge spell slots for making ad-hoc class power changes in AD&D 1e or 2e. A significant power boost that doesn’t increase over time would require capturing a specific spell level. You wouldn’t allow players to sacrifice their ability until they have a slot of the appropriate level. Upgrades with-level powers would be charged a spell slot at the highest level that the caster would have (meaning higher-level spells would not come later unless the player has very high attribute modifiers). These seemed to work well, and you may constantly be looking for a more straightforward and more effective way to teach non-spell casting classes.

Your player would have the land speed set at 20 and the other speeds at 40, respectively. You may also increase the creature’s size from Small to give it more HP. Would you charge her for a second-level spell slot once she reaches level 3?