Lot’s of bikes go through lots of rainy weather and have long lives…..personally I'd make sure my chain, cassette, chain rings and rear derailleur are grit free, cleaned, dry and then re-lubed after rides in heavy rain. I'd clean brake pads and rims too. Lubing the exposed springs in clipless pedals and cables can't hurt every now and then. If your frame is steel then ‘frame saver’ is a good idea if it’s going to be a rain bike.
Cleaning can be messy but it shouldn't take too long once you get a routine down….but then I like cleaning my bikes.

Your bottom bracket is protected somewhat by a front fender. Even a sealed one should be disassembled and cleaned after a rainy season ends though. If the chain etc. cleaning doesn’t fix it you might want to do that. Cleaning and re-greasing hubs once or twice a year is a good idea too.