1 more thing is that the companion seems too easy to levelup, and not very fun either just lots and lots of clicking to buy fruit and feed as much as you want until tired of clicking.
Might not be a bad idea to either make it to where companions can't eat unless they are hungry enough that eating a fruit wouldn't raise spirit hunger over 100.
And/or could make it to where instead of gaining soul growth xp per fruit eaten, could maybe change to where soul growth xp increases every time spirit hunger decreases. So this way as long as you keep your companion fed then will continue growing over time. Then growth stops at 0% until you feed again.
edit*
Actually maybe not too easy to levelup depending on what the cap is or if is capless. For some reason I thought maybe it would cap at 100. It depends though. Right now reaching level 100 is super easy. Currently am level 300 so would take me a while but could probably reach level 1k+ eventually at this rate. Is just a lot of clicks. Might be good to plan to cap at either lvl 100 or 1000 specially if can unlock multiple companions. I think capless could work too but in that case maybe better if capped by time via not being able to feed when full.
If we need to do a lot of companion feeding and with it being so inexpensive per fruit, might be nice if option to buy fruit in bulk like maybe x10 or x100 at a time or something.
Or instead of a x10 x100 purchase option, I like how can already hold down left mouse button to purchase multiple upgrades on the Cultivation page. So Might could also hold down the button to purchase multiple fruit in bulk?
If companion system were less click heavy then I think the bottleneck would fall on income from expeditions and become a money sink rather than an indefinite time spent clicking sink.
Hold down the button to feed though? That seems quite slothful.
Could also be worth mentioning in the tutorial how can hold down the button for multiple upgrades. Might could save somebody from alot of extra clicking lol.