I support Valve because they offer a great consumer experience and have made (and continue to make) PC gaming (on window, mac, and linux) a better experience. I certainly trust them more than EA or Blizzard in that regard. I vote with my dollar and they will continue to get it, so long as they continue to do good things deserving of my business.
Check around tho, other alternatives exist, and Steam...well, it'll continue to exist without your ongoing support, at the very least.
https://alternativeto.net/software/steam/?license=opensource
The primary reason I don’t use Steam for almost anything is due to its DRM policies. But it’s pretty easy to concede that Steam still does a lot of things better than the competition. One example is mod management through Steam Workshop - I eventually switched from my DRM free copy of Rimworld into Steam because running and updating 30+ mods for a game is just hundreds of times easier in Workshop.
However, it’s mostly easy to enjoy PC gaming outside of Steam these days with a little effort. GOG is a favorite platform of mine due to its history of anti-DRM policies and is viable for most of the stuff that I play (single player games). I personally am not a huge gamer and am only launching 2-3 games from Steam - the mod heavy games mentioned above as well as exclusives like Tabletop Simulator. The situation is a lot better than 10 years ago when Steam was really the primary and only choice for a PC gaming library.