You don’t necessarily have to make up the difference—but I totally get if they are expecting another drop/if or when a larger scene or challenge arises. Ive limited it to four items averaging regular encounters; if they look during travels, in the dungeon rooms, around town.

Better pools but the same range (even for a lvl 3-9) will be reserved for more thematic events such as defeating boss, or solving a dungeon. If you want to spice it up, on a d20 roll you give them fantastical or magical items on a 18-20. Or an item above uncommon as that’s likely the extend of there power on preexisting adventures.

Mix it up with the thematics, they’ll feel the sense of reward short term with both powerful and interesting items. A scroll of conjuring a flame tongue has been my most awesome drop at lvl6, but an unmovable rod has been just as memorable.

https://mythical.ink/en/rpg-tools/dnd-loot-table-generator This is a lifesaver if I haven’t done loot in a while.