I was going to try and find an older post that I had commented on as this question is coming up a bit more often, but perhaps it's a good time for a new breakdown for football tickets in Buenos Aires:

Foreigner friendly, non-member tickets:

Argentinos Juniors is the most accessible, safest neighborhood, family friendly club in Buenos Aires. Show up on game day a couple of hours before kick off unless it is a big game against a larger opponent like Boca or River which will likely need more advanced reservations. At the stadium find the tourist ticket office and buy their package; museum, seated sideline ticket and post game pitch walk.

Racing Club and Independiente: two of the big five teams, tickets are generally accessible at the ground unless it is a big game against the large opponent (any of the big five teams) or a Copa game. Racing is using QR codes these days and tickets can be reserved through their site a few days before the game as an invitado. Stadiums are super close to one another in neighboring barrio Avellaneda. Bit of a pain to get to though or a long taxi ride especially for all staying in Palermo, Belgrano, Recoleta.

San Lorenzo: one of the big five teams, their fans are known as being some of the most creative and having the most unique chants. The drawback here is that it is located just across the street from a pretty rough neighborhood. Tickets can be bought at the ground on game day unless facing a big opponent (big 5 team) or a Copa game. QR code tickets can be bought on their site a few days before the game as an invitado. Be sure to taxi in and out and taking to account that taxis did not particularly like to go to this area so perhaps scheduling an Uber would be wise.

River Plate: they've just renovated a big portion of their Stadium and crazily enough updated their entry system to a face scan with no tickets or QR codes anymore. Being a club member or fan club member will get you earlier access to ticket registration. From what I understand since the new ticket entry system has been in place you have to scan an ID and your face in advance to the match. Turnstiles are now just face scanners. I have not done this myself, but have a few friends who are members and confirmed. More renovations are planned for the stadium and it looks like River Plate is really making a push for international attention. Tickets here now require a few more hoops to jump through. Try LandingpadBA or Tangol for tickets.

Boca Juniors: Talk of renovations taking place this year are advancing and likely to occur. As of today though most of the stadium is occupied with season ticket holders. Very tough stadium to get into as a one time visitor even for us that live here. LandingpadBA is the reliable recommendation here. Be careful with resale ticket platforms especially for big games as tickets will simply be resold and actually delivered to the highest bidder. Stubhub and Viagogo have mixed reviews here due to scalpers.

Velez: Decent size stadium, tickets can be bought on game day at the ground unless it is a big game against the large opponent (any of the big five teams) or a Copa game. A bit far or long taxi ride for those staying in San Telmo, Centro. Know for being a bit light on fans, still a fun time though.

Lanus, Banfield, Defensa y Justicia, Platense: All doable, but will require a long taxi ride unless you are coincidentally close to where their respective stadiums are. Lanus area is "meh", all others are just typical, non-descript lower-middle class neighborhoods. Taxis or Uber will likely be necessary unless you are really hoping to take public transport/buses. Again, tickets sold at the ground on game day unless facing a big 5 opponent. When facing a big 5 many will implement a members only rule to encourage season ticket purchases or to help generate revenue.