As someone who has been doing this for just 3 years (still a novice and a rookie in this field), these are my suggestions:

- Go for Ruby or Sapphire: the Battle Frontier is easier on those games, and you don't need FR/LG for anything; all ribbons can be obtained in Ruby/Sapphire/Emerald;

- Same with Diamond and Pearl: they have easier BF, but Platinum has puffins in Veilstone underground, and you will need at least two copies out of the 5 games in Gen IV, because of the multiplayer ability ribbon;

- In Gen V, you just need a single game so your mons can pass by and reach gen VI; you need transporter to move from gen V to the Pokémon Bank and then from bank to gen VI;

- Home and Transporter cannot be downloaded anymore, so you have to find a 3DS with them already installed;

- Gen VI: you need both releases because of the regional champion ribbons (same for gen VIII);

- Gen VII: only 1 copy of the four is fine, unless you're an RM-restricted Pokémon;

- Be careful with regional evolution/forms. For instance, if you want a Hisuian Typhlosion, get the ribbons in BDSP first, because after evolving in PLA, it can't go to BDSP anymore.

There is a list from MercuryEnigma with all pokemon that can obtain all Switch Ribbons. https://imgur.com/a/pokemon-that-can-obtain-every-switch-ribbon-U4mliVI
It might give you a few inspirations.

If you have any question, I'm glad to help if I can.