How do you organise your 5 AR raid teams?

Just build one team with the bonus units that can have a good chance at beating the biggest threats and call it a day.

Im not gonna waste my time, have other things to do haha

Well, I've only built a single team and I've only ever lost 2 units once. It's a matter of luck IMO.

That being said. I'd get an anti Rein/Lyn/Veronica team, a anti rein/lyn team (no veronica opens a spot), a anti veronica team(1 unit to make sure you can at least tank her), and then 2 teams for your favorite (most common) and a anti meta team (or something along those lines).

Just look at the most common threats and organize based on that.

I'll share what I used last season.
Principal team: Nowi+5 summoner supported +spd -res (want -HP), Lewyn (virtually neutral), B.Celica (neutral, base kit with QP seal), Alfonse. A generalized team with two attackers, including a galeforcer, and a general-purpose tank. Nowi and Lewyn are the stars here - Nowi, because she'll tank the hell out of anything that isn't dragon-effective or a green mage (notably Aversa), and Lewyn because he'll blast a lot of stuff to bits and he can be good at hitting people's aether pots.
Second team: Zelgius +res -HP, L.Hector +atk -HP, Felicia+7 +spd -def, Fjorm (neutral). Fought some of the armour teams that my principal team was less good at handling (ex: due to traps preventing Lewyn from diving in and Nowi being unable to tank the enemy that he would have taken out if she wants to reposition him out)
Anti-cavalry team: H.Henry +def -atk on Gronnraven+TA, Micaiah +def -spd, YT Olivia, Fjorm. Henry will humiliate Reinhardt, B.Lyn, and Veronica; YT Olivia is needed in case there's a green on the enemy team because Henry has around 41 atk.
Cavalry team: Reinhardt, B.Lyn, SM Eirika, Fjorm. Fjorm was crucial as a tank. Reinhardt sniped an Aversa or two. This team was effective against a few enemy teams that were quite campy but had a very large amount of firepower focused on a choke point. If I couldn't snipe Aversa
Flier team: F.Grima +spd -res, Camilla +res -def (will change this one eventually), WF Hinoka +res -def, Fjorm. Won for me on some maps where terrain was an issue. My fliers warp and reposition all over the place.

In general, what's important is to have a range from hyper-offensive to very defensive. Hyper-offensive teams (often with enemy phase options) are necessary for dealing with defensive setups that try to stall out the 7 turns; very solid defensive teams are what keep you death-free when you run into teams that are (foolishly) built just to take out one of your units and then lose.

Dancer, Healer, Chipper, Passive Debuffer, Bonus unit.

Currently my core group involves Veronica, Jaffar, Loki, Aversa, F! Oliva. Staff users who hit hard are the new meta.

Then depending on who is the bonus unit I swap them out.

Doing nice with Soren at +2 (without skills), Aversa with default kit + reposition and hp/res 2 SS and A!Tiki +8 with BoF eff refine, DC vantage, drive atk and heavy blade SS and Ursula as bonus unit (keen wolf+ spd refine, db3, sword breaker, hone cav). Ursula and Soren does 90% job tho, so no need to merge anybody up to +10.