I’ve had home built beater winter bikes since about 1980. One even rusted through at the bb and the frame bounced and the pedals hit the ground on the way home. I try and use an old or inexpensive new big box bike frame. You really can’t protect stuff here with mudguards as the salt gumbo fills everything up and then the next day the wheels won’t turn. Our roads are loaded all winter with a salt/sand gumbo. My bikes last a few winters before the brake mounts, chain and derailleur become unusable. Then their donated to our volunteer fire department scrap drive. Every spring and fall I soak everything in penetrant, but the canti brakes are always stuck and the chain is a solid piece. Lots of oil and a few days winter riding brings it back, but eventually it just won’t work. Once you have to start sanding the rust off the canti mounts, forget it, it’s shot.