You’ve pointed out problems with (shadow)bans of organic, real person profiles & the uncontrolled spread of right-wing misinformation & propaganda. I’m not talking about accounts of politicians. Politicians are not everyone’s peers. People more strongly engage with messages spread through their network of peers.

That’s why I’m suggesting adopting the same propaganda machine tactics. That includes bots feigning right-wing accounts to gain clout with right-wing communities, then when they have enough credibility, deftly inject left-wing ideas into “right-wing propaganda”, spread misinformation damaging the right, denounce right-wing figures as not “right-wing” enough. Fight lies with lies, inflame tensions, cut rifts into the right.

Since you’re referring to Brazil, another article on the topic mentions

To Brazilian sociologist Sérgio Amadeu, “online social networks and platforms controlled by big tech companies are geopolitical structures increasingly aligned with the far right.” In June, at seminars held by Bolsonaro’s right-wing Liberal party (PL), executives from Meta gave workshops teaching how to use AI and achieve greater reach on the platform.

The left could very well do likewise to “use AI and achieve greater reach on the platform”. Instead of resist and try to restrict the lies & propaganda, they could embrace & turn the same tactics against them.

they would never allow such botting for left wing ideas like they do fascists.

I’ve yet to see that. Social media like reddit is overrun with bots & fake content that they seem unable or uninterested to prevent. It’s an arms race between platform operators & bot operators working new ways to raise & defeat moderator controls. Shit gets through anyway. It’s a matter of competing & doing in kind.

mainstream online platforms themselves are not neutral

Unless you mean they’re not neutral about whatever yields income, I’m not sure that’s conclusive. Their “algorithm” optimizes for keeping users online regardless of what does that. A particular political orientation isn’t necessary to do that. That current ragebait predominantly leans right-wing may just reflect who’s putting the resources to sustain a ragebaiting campaign & evade bans. While I’ve seen signs & reports of the right gaining influence through viral propaganda & attempts to dominate mainstream platforms, I see little sign of the left seriously doing that.

When foreign adversaries weaponize social media, instead of putting out one-sided propaganda, they target friction points by trying to manipulate people on both sides. They’d not only push supportive propaganda, but also radicalizing propaganda to discredit the “supported” side to itself & inflame divisions.

Maybe some propaganda is needed to inflame right-wing divisions & exploit their contradictions. Left-wing propaganda could be put out in guises that appear right-wing and probably catch on: the right isn’t exceptionally bright.

The left does ignore this problem or get wrapped up in their useless “big picture” rhetoric that leads nowhere when this is a very practical, tangible problem. Dominating over the right-wing propaganda machine is the obvious answer. When I suggest the left needs their own propaganda bots & troll farms flooding social media, their own podcasters & influencers to propagate their propaganda, better engagement through local organizations to answer & counteract right-wing bullshit & push some of their own to keep the right-wing occupied, I get responses like

This is such a boomer take. This is like trying to claim Clinton lost in 2016 because she didn’t tweet enough or use the right young-person slang, skibidi

or digressions like the comments here that dismiss everything as another problem to pin on capitalism without offering constructive ideas that could seriously lead anywhere. A left-wing propaganda machine to outdo the right-wing is doable, I doubt propaganda bots would cost a fortune to set up. The loser mentality of just venting about impractical shit instead of organize & reach for practical solutions is a major part of the problem.