"Also- should I enter a max of $53/mo under miscellaneous expenses?" "I was (optimistically?) under the impression that the Bicycle Commuter Act of 2019 (or similar) would come into play here".
The Bicycle Commuter Act of 2019, with the max of $53/mo, would allow an employer to provide a tax free employee benefit. It never allowed an employee to get a direct tax deduction. The Act would restore the benefit eliminated with the 2018 tax law. i don't believe it ever passed.
It would also not apply to a self employed person claiming expenses on Schedule C. You can deduct all your actual expenses. On the other hand if you are a W-2 employee, you cannot deduct any of your job expenses, including bike repairs.
