At the very least, I'm inclined to adopt a wait-and-see attitude. It would be a good step if the DOJ started trying to enforce monopoly laws as actually written, but this administration really isn't well-positioned to do that.
Trump has shown a willingness to back down if he gets enough pressure from Republican congressional leadership, particularly if there's an accompanying public outcry. If tech stocks take too much of a hit, investors and operators of potentially affected businesses like mutual funds will get nervous. Other large, non-tech companies that are taking a long view will also get nervous. Even if they aren't current targets, precedents could be set that would bite them down the road. They have a vested interest in keeping the DOJ intepreting the law the same way Reagan's DOJ did.
Trump hasn't always taken conservative positions, but he mostly has since taking office. That's part of what keeps his base happy. Much as he dislikes Bezos because of the Washington Post, is he really going to embrace a position advocated by Elizabeth Warren? At the very least, that isn't going to look good to some of his supporters--and many of his donors.
Then there's the economy. Trump's approval rating isn't great to begin with. In fact, throughout most of his administration, it's been at a historically low level. However, it isn't cratering the way approval ratings did for presidents with similar problems (like Richard Nixon). Aside from the tapes, there's actually a larger body of evidence against Trump (or at least the way his administration does business) than there was against Nixon, yet Trump's ratings are higher than Nixon's during Watergate. Partly, that's because the country is more polarized, but partly, it's also because of the perception that the economy is in good shape. (Nixon was fighting an unusual combination of inflation and recession at the same time.) Keeping in mind that the trade war with China is already having some negative effects, what happens if stock prices fall and stay down as a result of DOJ and FTC activity? What happens if other economic hiccups occur as a result, like companies postponing expansion to see what happens? Trump's approval ratings will start to drop, something he really can't afford politically. (He's already losing to Biden and Sanders in one-on-one match-ups by a decent margin and only breaking even with Democrats who have less name recognition.) At minimum, if he really wants re-election, he has to hold on to what support he has. Slowing the economy is not the way to do that.