If by “these days” you mean a motherboard that supports UEFI, then it honestly doesn’t matter anymore. Your board controls the boot order, and there isn’t an MBR for Windows to mess with anymore. Just plan out your partitioning careful before hand, and if you plan on using a lot of files in both OS’s, make a plain storage partition that is easily mounted under Windows (NTFS does not count).
Honestly, aside from a very scant number of apps or games, there isn’t a real need to dual boot anymore. If you can’t run something under Proton or Wine, having a Windows VM will get the job done.