Was Pompey losing his grip in 54 BC?

Pompey never had a 'grip'.
He was a puppet - To his financiers and debtors.
Also a victim of his own desire.
Which his financiers made 'abundant'.

It would help to understand one of the most ancient of Roman concepts, which was the soci (singular, socius). In its oldest form it meant a sharer--and can be seen as meaning a companion, or an ally or an associate. Of course, associate has that as its root, as do social and society.

For the Romans, the soci could be patrons or protégés. The more you had, the greater your influence, and that worked both ways. Someone patronized by several prominent people had much more influence and potential political power than those with few such associates. Someone with many protégés could have a great deal of influence and power if those protégés in turn had many protégés, as well as other influential patrons. One's power ramified through those contacts. Pompey was, of course, a member of the order of Patres, and tended to ignore men from the order of Plebs, and as were many Patrician, was contemptuous of the order of Equites, the equestrian order, the "new men" in the republican empire.

Gaius Iulius Caesar did not have this problem. His was a provincial branch of the Iulia gens. (Please note that I use "I" because there was no "J" in the Roman alphabet; I am not suggesting that you do the same, it would probably only confuse your readers. Modern English speakers would refer to the Julia gens.) Although one of the oldest and most influential of gens, Caeser was, in effect, a country bumpkin cousin of the gens. His popularity, however, was built upon his soci, and as he was not haughty, that popularity ramified throughout Rome and the republican empire. He was also enormously popular with the legionaries who served under him. He went into battle with them, was visible throughout the battlefield, and he endured their hardships. Under the Roman military system, and man who was wounded in battle, whether only temporarily disabled, or permanently disabled, was returned to his recruiting depot, and the mystique of Caesar therefore spread throughout the armies, and the lower orders--Plebs or Equites. Despised by the Patrician order, he remained a darling of the crowd in Rome, and was as well regarded in the provinces.

As for Pompey's relationship to Julia, that is two thousand year old gossip. I don't say it's wrong, and as an author, you are entitled to make as much (or as little) of it as you choose. His failure to go to Hispania robbed him of an opportunity which Caesar had exploited himself. He had campaigned in Hispania in 61 and 60 BCE, defeating the Lusitanians. When he was given the consular power in Cisalpine Gaul in 59, he used two excuses to go into Gaul and campaign. One was the death of the governor of Transalpine Gaul, and the other was the alleged invasion of Transalpine Gaul by the Helvetii. While Caesar was building his military reputation and his popularity with the army and the lower social orders, please excuse the expression, but Pompey spent those years dicking around in Rome. An obsession with Julia is as good an explanation as others which historians have advanced--and although I don't know this to a certainty, that might be the majority opinion of historians.

I wish you luck with your project, and encourage your to look deeper into the social relationships of ancient Rome, and how effectively Caesar exploited them, while Pompey lost those opportunities because of his patrician hauteur. You don't have to take that line, but it seems to me to be undeniable that Caesar was "a man of the people," and Pompey definitely was not.

'Darling of the crowd in Rome'?
Were you in that crowd?
How do you know this?

I'll tell you how - For it is academically regurgitated as being the commonly held belief.
Yet - You well know that history is biased toward the victors and authors thereof.

Nero might have been a pacifist and attempted to disband the war-machine, for all we know?
Unlikely his 'demonisers' will record him as such?

Not knocking you or your memory-storage capacity - Just the origin (Source) of the rumour.

I suspect that you know about as much about historiography as you do about science--which is to say, nothing. You believe what you want to believe. It was Napoleon who said that history is written by the victors, so you are the one regurgitating a commonly held belief. Even the French of the day were not fooled. Napoleon sent out bulletins after each battle, and it became a common expression among the French that someone "lies like a bulletin." As for Nero, Gaius Suetonius Tranquillus, who wrote the lives of the Caesars and who loathed Nero, praised him when praise was due, such as for his compassion and relief of the Plebs after the great fire. The more I read of the drivel you post the more convinced I am that your education was wasted and that it is you who puke up the common "wisdom."

Wonderful insight, can't thank you enough!

I'm glad to think that I might have helped. I wish you the best of luck with your endeavor.

Thanks for your 'Napoleonic-divergence' retort.
Was bollux, as expected.
Who Else, but the Victors, inscribe 'history' ?

I get that you are 'reactive', needy for validation and an 'alpha' (In your own mindset). But you talk bollux - In a clinical fashion.

You have NO valuable thought-processes - You merely memorise academical historical data and regurgitate it ..... constantly.

But, you have a kinship with dogs. I like that, and forgive you your trappings.

Point being (Didn't know Napoleon said that - If he did?)
If you didn't witness it - It may be untrue or embelished.

So why do you present your regurgatative knowledge (hearsay) as empirical fact/s?