I don’t really think there’s such a thing as taking self shipping “too seriously”, and I think it’s absolutely fine for someone to view it as a real relationship.
Any argument someone can make that focusing on a fictional relationship instead of getting a ‘real’ one is somehow harmful would be aphobic and amatonormative.
There is nothing that says you should prioritize a relationship with a real person.
As long as you’re happy and doing what you want, where is the harm?
Live your live the way you want to, and enjoy yourself.
Also there’s nothing that says you can’t have a serious self ship relationship AND an irl relationship.