Rust mitigation in rear wheel wells

[SpaceSputnik]

Hey All

I have a Canadian 08 Hatch and a family member has a shiny "new to them" 19 hatch. The areas in front of the rear wheels are basically big pockets where all the dirt/salt collects. The 08 has a certain amount of surface rust that slowly progresses over the years (not talking about sheetmetal, but the structural metal in front of the rear wheels where it forms a horizontal shelve). Not too bad yet but makes me wonder what would be a good long term mitigation strategy for both cars. Rust paint, regular spraying with Rust Check aerosol, etc.
Willing to go to certain lengths as long as it is long-term effective, open to have done stuff professionally etc. These little cars are just too good to let them rot.

Anyone has long term experience keeping that at bay in snowy climate?

Thanks.

PS I am not actually a new member...had an account for long time, just can't seem to recall the details.