Gambling can be said to be rational when calculative processes has been applied in winning a particular game when staking. No serious minded gambler stakes without applying certain critical and logical tools. The process and ability of subjecting your plans into achieving success while placing a bet is what defines the rationality of betting in gambling.
I do not believe this is where the rationality of gambling is assessed. What critical and logical tools can a gambler use to increase his chances of winning? None. Even AI does not guarantee accuracy.
In my opinion, rationality is not the strategy or tools we use in gambling because we cannot predict the outcome of a game regardless of the tools used, so the more we look for a more sophisticated tools, the more likely we are to lose, and the seriousness you mention becomes unreasonable when a gambler is not winning.
My submission is that being rational entails taking charge of what you can control, such as your time and finances. A gambler who does not spend a lot of time gambling, in my opinion, is rational. A gambler who sets a fixed stake and sticks to it to avoid irreversible loss is rational.