A particular usage of the word 'had'

My question stems from the usage of the word 'had' in contexts indicating consumption. For example: "I had a glass of water." A second example: "I had a great time."

My traditional understanding of the word 'had' derives from the infinitive "to have." I thus thought that this may be a second definition of the word where it means "to have consumed," or that it may simply indicate possession accompanied by an understood implication of consumption.

An alternate explanation I thought of was that it means what it says: "I had a glass of water." This being past tense, the speaker no longer possesses the glass of water, and the understood meaning is that they no longer possess it as a result of their consumption.

A secondary question would be how to indicate the alternate explanation without the inference of consumption being made by whomever I am addressing.

Any thoughts on this would be welcomed.

Thank you!

There should not be any confusion involved with your examples.
The verb to have does involve possession. And it can be used to assist other verbs in establishing a time frame for action.
To have also has been, and still is, used to avoid using other verbs in polite speech. We still hear this often. "Will you have some fish?" still sounds better to most of us than "Wanna eat some fish?",
In times past many considered base human functions such as eating or drinking as too vulgar to state plainly. So, subtle ways were employed to avoid sounding common. "Will you take wine with your meal, sir?" , "Will you have the steak or the chicken?" "I had a little sherry with the cake."
Today one may drink a glass of water, or have a glass of water. The difference in the two is that the have form can be extended to mean something other than drink. "I had a glass of water but never touched it" would be a way to say I had water but didn't drink any.
The subtle older uses are still understood and entrenched in our speech. It would be best not to worry that the meaning of "had a glass of water" might be misunderstood. It will be understood as "drank a glass of water" unless the statement is expanded to indicate a different meaning. Such idiomatic usage will remain with us until there might be a problem with understanding. Should that happen, our language will evolve, as it always has, to correct the difficulty.