I play both self-insert and non self-insert games, and I like both. Both should be allowed to have their space in visual novels, and I don't think you should feel forced to make a self-insert if you don't want to.
On the one hand, I understand that self-insert being so popular would lead to more eyes on the game and more sales, which is something that can make it so enticing! But as you said, you'd also have to spend a lot more money and time to make that alternative.
Sadly, you can never please everyone, and I would love if people would still give stories with a set MC more of a chance. Self-inserting isn't the only way to enjoy a story, after all!
Personally, I think you should do what brings you most joy, but when we're so trapped by the expectations of the public, I can definitely understand the hesitation.