Oh yes, they *did* something right: their app, right before all these "free updates to boost your system plz gib gib". You're telling "4.8 stars", I tell you "4.8 stars based on their previous versions".
I would not have cared if they decided to make it a paid app; I have a handful of these when they feel polished enough. I even paid for a basic SMS app that was just a "downgrade" for the recent stuff google pulled on that.
But the thing here is that they are shoddy. Consumers trust is hard to gain, and when you lose it, it's done. When you have arguably one of the best app on the market that does a lot of things well, there's one thing you don't do: start behaving like it's a chinese ripoff that exist only as an ad channel.
On the point of ES File Explorer: one day, out of the blue, my phone had a notification about "removing trash to boost the performances", or something along the line. It sort of looked like a classic spam message, with no indication that this was from an app. And if dismissed, it comes back quickly. That was ES; and there was no option to disable it. Then, this "extremely useful feature" became the default screen when you open the app, prominently taking a third of the screen to encourage you to use what have all the warnings you're looking for when you look at a scam.
And now, the very same team decided to force-feed you a new lockscreen, with implications that goes well beyond the "showing ad" issue. Android might not be the most secure thing on earth, but I have slightly more trust in the stock lockscreen than in the one provided by some definitely shoddy business.
Seriously, now I've removed all of their apps, found very good replacements that don't do anything funky, even paid for one, and all is well. But I can't understand how you can think "hey, let's force spam and bloatware down people's phones, THEN make a paid version without that" when you could have just done it harmlessly.
They could make the best app ever now, I'm never trusting them again with anything.