I'm not sure if I would count this as five games or not, but beating Dream Radar is way less of an obstacle than doing 80% of Emerald. Also imo DS/Lite req for Pal Park<3DS req for Dream Radar. Pokewalker comes with HGSS. So G5 Nat Dex is easier than G4 Nat Dex by a hair.
lost my pokewalker as a kid, never had RSE, my only ds lite is too worn out to actually use anymore, 3ds only g5 natdex was MILES easier in my case and i still had to phone a friend for teddiursa and groudon for my heartgold
Tbf losing the Pokewalker is kind of a you problem since it literally came with the game, on the other hand G4 Nat Dex REQUIRING Pal Park which only worked with the first two consoles in the DS family must have been a huge kick in the pants to anyone who made the reasonable choice of having a DSi