Have somebody come in, measure, and fab a door that swings out (assuming you have room for that - can’t see in your photo). Even in LA this shouldn’t cost more than $4-5k.
If you have to replace the whole shower wall (it may be cheaper, or you may not have room for a door to swing out), then even replacing the glass wall-to-wall shouldn’t cost more than $4-8k.
If you know somebody, it may cost less. If you do the demo, it may cost less. If you can buy a door or a wall at Lowe’s (or wherever), it may cost less.