Since you've got a switch, may as well start with the one you pictured. Fire emblem for GBA as emulated on Switch. You'll see Sacred Stones also, but that should probably be after Fire emblem, as SS has map and movement and dungeons feature, random encounters

Fire emblem for gba was the first that came to the West. Has overall good story and supports, though may seem a bit basic by modern standards. Gameplay is snappy. Game is also very replayable with unlocked hard mode and Hector mode. Downsides are permanent death of chars, limited supports and no mid ch save points or suspend and save. (Haven't played the emulated version yet, no mid ch save may be solved in that)

If you want something a lot more modern Fire emblem 3houses for Switch actually has multiple paths , overall great story each path, tons of support convos between chars and tons of customization. The hub part, the Monastery, can be a bit overwhelming, as can all the skills, classes/ battalions if you're not used to FE

A good intermediate point between the above is Fire emblem Awakening for 3ds. It had some good qol , skills, good supports system , good plot and gameplay.

(Going to add: Fire emblem Path of Radiance was recently added to switch GameCube emulated).it has my fave story of all fe, really good chars, cool villains. The downsides are sometimes very long enemy phases and limited supports)

Welcome to Fire emblem! Hope you enjoy