Some examples:
I haven't ordered anything on Amazon since 2014. I hope the rationale is pretty obvious. I lean heavily into brick-and-mortar and especially local stores, where possible (I'm blessed with many local book and music stores). I do use eBay, and occasionally (maybe 1 in 10 purchases) I find out that the seller is actually just doing arbitrage from Amazon - they buy a $10 item on Amazon for $5, and have Amazon ship it to me using the "gift" feature. $5 profit for them; lots of bad feels for me.
I don't subscribe to any of the streaming platforms. I believe that I should have a tangible video that can't be clawed back, so that means buying a lot of DVDs and Blu-rays. Blu-rays, I know, are a tower of cards, since my ability to play them back indefinitely relies on leaked keys. If I want to watch a "Netflix exclusive", like Stranger Things, it means I'm organizing a watch party with friends who have subscriptions, where I'll provide food and beverages to at least attempt to offset that I'm benefiting from a streaming platform.
I listen to a local college radio station, instead of Spotify. I love that there are human DJs curating the playlists. They're creating community (the station actively engages the community), and since they're mostly college students, they're learning a valuable skill for their futures as well. Since laws around public radio prevent them from selling advertisements, I donate to the station in excess of what I'd pay for Spotify, since I value it. For buying music, my preference order is Bandcamp (DRM-free FLAC; the artists actually get a decent cut on the sale), followed by physical CDs (see the tangibility comment, above).
I run my own e-mail - both inbound and outbound. This is because I am stubborn, and have done it for twenty years now. I know Gmail and Outlook are on the receiving end of 90% of the e-mails I send, so they have a copy of most every message. The maintenance makes it a Pyrrhic victory.
I abstain from social media entirely. Hacker News comments are about as "social" as I get in the public sphere these days, as they capture the spirit of what I loved about the Usenet/forum days. I do participate in some professional Slack networks. Much as all of those networks would prefer _not_ to be on Slack, it'd be too hard to up and move the communities.
I could go on, but the gist is that I know these decisions are helping me, more or less exclusively - they don't even register in the overall trend.