Many cats are perfectly suited to be indoor cats, it really does depend.
Anecdotal: I have a feral rescue who they told me couldn’t be rehabilitated into an indoor cat, but after a month of being exclusively indoors (unintentionally, I had to move out of my house for mold treatment), his anxiety was almost completely gone and he started being friendly and affectionate to everyone who gave him attention.
Many cats are perfectly suited to be indoor cats, it really does depend.
Anecdotal: I have a feral rescue who they told me couldn’t be rehabilitated into an indoor cat, but after a month of being exclusively indoors (unintentionally, I had to move out of my house for mold treatment), his anxiety was almost completely gone and he started being friendly and affectionate to everyone who gave him attention.