lineups

how many recon lineups would u recommend learning for each map

depends on the map
but take ascent for example

I would try learn: 2 for each site on attack (one is needed but imo 2 is preferred), a retake dart for each site
darts to clear bot mid from tiles and top mid

i might be missing some
I'm gonna try main scan eventually but I haven't gotten around to it yet

Personally I like to have one for early info on defense, one for retake on defense, and one for execs on attack, for each site as well as mid. However, this is very very basic and generalized and the number of darts you'd want to learn entirely depends on the map; sometimes there are other lineups you want to have (e.g. attacking A Long dart on Haven) and sometimes the darts you want to learn are as simple as chucking the dart at the wall (e.g. an anti-rush recon for Abyss A). My advice is to try playing a few games on the map, noting down any time you think you could use a recon lineup, and finding one for it later.

Recon lineups, as many as you're willing to learn. Aayan's comment is a good start but there's a caveat -- people adapt lol.

I've learned that a lot of people that try to learn lineups for attack side just end up using the same one or two every single time so it gets predictable. And often (at least when I solo q) the Sova player just kinda short-circuits because their precious lineup was solved and proceeds to do nothing the rest of the round. So, I personally didn't bother to learn many recon lineups. I like to wing it often, and that randomness usually catches someone off guard because they expect the recon to land in the same spot every time.

For defense, there's a lot of power to anti-rush darts. Like right when they're executing a site, just hucking a recon at the back wall as they push out usually gets me or a teammate a free kill through a smoke because they either have to run back to main or turn around and try to break it, and again having some randomness and chaos to it makes it easier