Below 20 mph, standard bike helmet is acceptable. All will provide the same level of safety as long as they are CPSC certified.
Above 20 mph, DOT-approved (or SNELL equivalent) motorcycle helmet is recommended.
Full face is best, but understandable to skip on if you’re in super hot weather. That said, a lot of faces have been save from full-faced helmets.
The Giro Bexley MIPS looks sweet, but it is no safer than any other CPSC bike helmet.