Good on you for already sharing some feedback with your colleagues.
Given that your initial feedback didn't have the desired effect, here are some potential follow-up options:
1. More feedback - Don't be afraid to give the same feedback more than once. Offer concrete examples of the behaviors you dislike and how they effect you. E.g., "Yesterday I saw you ..., and it made me feel ... ."
2. Suggest new working norms - If the behaviors happen in specific circumstances suggest norms that mitigate or pre-empt those circumstances. E.g., if your colleague routinely fails to prepare for a presentation, suggest that your team have regular check-ins (15min every morning) where individuals share progress on their tasks and can ask for help or escalation.
3. Talk to a confidant - Sometimes it helps to share feelings and let someone else share a perspective on the situation. Consider discussing your feelings with a trusted colleague in a different department, a close friend or partner, or a psychologist.
4. Create distance - You said that not working together isn't an option, but could you work in a physically removed space (e.g., take a laptop to an empty meeting room) to give yourself some time away from reminders of your feelings?
5. Stop fire-fighting and proactively offer help - It sounds like you're picking up the slack of your colleague. If this often happens at the last minute, stop intervening in those final moments to "save the day" and instead offer your help earlier in the process. If it is declined, share your concern about potential failure.
The other ideas in the comments are great as well. Let us know how it goes.
Looking for strategies to reduce my irritation and accept the
I don't think I answered this straight on. #3, 4, 5 may be all that is relevant to you. Regardless, I encourage you to consider what you can do to help your colleague improve (e.g., more feedback) -- both for your sake and his/hers.