I don’t like the horses/Pegasus/wyverns. I like the on foot units more. They seem to have higher attack and speed which is what I rely on. I generally have lots of swordmasters.
Pegasus Knights (historically) have the best speed growths in the game (and res/evasion)
Wyvern knights (historically) have some of the best defense.
and i have found on two of three paths - mobility is key.
i basically have two classes for my team.
Team Flight, Team Foot (and i barely every need team foot).
I'm finally on the Black Eagle path and i am legit training Edelgard to be a Wyvern Lord because I don't want to deal with her armour butt. (I mean i WILL, but. yah. she's gonna be a flying lol)
I'm generally split 50/50 in terms of units with canto vs units without. I have Marianne use the Stride gambit at the start of every battle so except for the massive fortress maps I can usually get even my non-mounted people where they need to be pretty quickly. I wanted to use Ingrid more because I got her to Pegasus and then Falcon knight but so she's useless against armored units. Usually end up rotating between Ingrid, Ignatz and Catherine for the last spot.
the only person i haven't ever made into a flier was Felix. (and i am half tempted to, just so instead of warp him into a pile of people, i can fly him into a pile of people dismount and he can continue to kick the behind.
I've given Ingrid a C in swords (usually how she is when i get her), and she can do fine vs. Armours if she has an armour slayer or a rapier.