If the default furnaces are too small for you, take a look at this mod.
Jumbo Furnace 1.19.2, 1.16.5 and 1.15.2 is a mod that will allow us to make, or rather build, a large furnace, with a much larger inventory and allowing the simultaneous firing of up to nine objects. The Jumbo Furnace is built by placing twenty-seven furnace blocks in a cube, or area, of 3x3x3 blocks.
The large furnace that will allow us to build this mod can be connected to other inventories through the use of hoppers. The upper face of the Jumbo Furnace will allow the entrance of elements, the lower face allows the exit of objects and the lateral faces allow the introduction of fuel.

How to install Jumbo Furnace Mod for Minecraft?
- Download Forge
- Download Jumbo Furnace Mod
- Double click on the downloaded Forge file to run the installer.
- Paste the downloaded mod file into the .minecraft/mods folder
- We can now build the large oven offered by this mod!