Fatigue campaign in Adwords

#1
Until recently, the client had excellent daily conversion (3-6) and the traffic, on manual control, increased the daily budget for this business. Over the past week, both traffic and conversions have dropped dramatically. The daily budget has ceased to be unscrewed, Google does not give impressions, the conversion has decreased both due to the drop in traffic, and by itself. Raising bids, reloading campaigns, cleaning up and adjusting doesn't help.

For other clients, I also observe this situation (and they have already written about it on the forum). At first, advertising in an advertising campaign goes off with a bang, applications are received, everything is stable. and then one "fine" day two scenarios begin to replace each other: a sharp and quick drain of the daily budget with low conversion or, on the contrary, a sharp decrease in impressions and traffic. How to influence this? There is no change in demand in topics, it is constant, the auction, let me remind you, has nothing to do with it either.
 
#2
Until recently, the client had excellent daily conversion (3-6) and the traffic, on manual control, increased the daily budget for this business. Over the past week, both traffic and conversions have dropped dramatically. The daily budget has ceased to be unscrewed, Google does not give impressions, the conversion has decreased both due to the drop in traffic, and by itself. Raising bids, reloading campaigns, cleaning up and adjusting doesn't help.

For other clients, I also observe this situation (and they have already written about it on the forum). At first, advertising in an advertising campaign goes off with a bang, applications are received, everything is stable. and then one "fine" day two scenarios begin to replace each other: a sharp and quick drain of the daily budget with low conversion or, on the contrary, a sharp decrease in impressions and traffic. How to influence this? There is no change in demand in topics, it is constant, the auction, let me remind you, has nothing to do with it either.
Some campaigns have the same problem. For a couple of days, it is decided by copying and starting over. Then on a new one. Or the inclusion of auto-strategy, but then the goal is much more expensive than the manual one. In general, a double-edged sword, either cheap and without traffic, or expensive and with traffic. In general, this is not the first time I have heard about this problem, they often write in thematic chats.