the airline may not be doing any preboarding on your flights.

travel with the least amount of carry on stuff. Wheelchair assistance is a good idea. Don’t forget to tip the person pushing your wheelchair as they are all on very low salaries.

Your cane will likely taken from you and stored by a flight attendant. I often use a telescoping cane to avoid that. It fits in my small carry on bag.

i have never been asked for any proof of need.