Signal data needs its own energy

Bottlenecks feel horrible. So I want to say first off that I get it, and I'm sorry you're feeling this. 

But after that, I should mention that it's a resource management game. We can't really have a game if everyone has all the resources that they need to keep boosting relic levels. Everyone will quickly achieve the same roster -- all the good toons at r10. 

This is the current balance, and in the current state of the game, like every state before this one, there is a bottleneck. Right now it happens to be signal data. In the future it will shift again and be something else. You're going to have to find peace with that if you want to enjoy the game over the long term. 

In the meantime, like you I'm taking only the briefest of breaks from SD farming for shard farming. Every day I spend 300 crystals refreshing cantina energy. I keep pushing forward the best that I can and reassure myself that everyone else is getting SD at the same, slow rate I am. 

I dislike cantina farms as much as anyone, because it interrupts signal data, but it's a "choice" how much it does. There's no refresh cost for cantina nodes so you can spend as much or as little as you like on them.
The cost to farm a new character's shards will be roughly the same, only the time will change. So, I usually treat them like any other farm, do 5-10 attempts per day and the rest goes back to signal data. If I needed the character as soon as possible I might focus just on the shards but that's less fun to me.
Normally you won't get any major benefits because you need the rest of that character's squad finished as well. And cantina farms tend not to be the last member made farmable, which would change the math. 
Psychologically, it all works out the same, you either slow your shard farm or your signal data farm, but its up to you and how you do it. Just don't try and do multiple cantina shard farms at once. 

You say that as if SD were the only components for upgrading relics. The requirements for almost each relic upgrade are exhausting and tedious, and it's getting worse. Especially now with R10. Farming SD is already long enough as it is. Having to pause it to unlock characters is just frustrating, especially since 90% of the characters you farm aren't satisfying to play, just requirements for other characters, for territory battles, or boring, uninteresting raids. And that's on top of farming kyrotech, relics, and other things. I feel like I have to farm a lot more than before, for a much less significant and satisfying result. But I guess that's the new way to play the game, and I'm looking for something that no longer exists. Too bad for me, but as long as some people like it, so much the better.

I don't know what to tell you. It's a game. Play the game to have fun. If what makes it fun is skipping the new releases and waiting until they're accelerated so you can spend more time farming Signal Data, that's an entirely valid choice. There is no winning SWGOH. You either have fun or you don't, that's the whole point. If Civ or watching old episodes of Star Blazers gives you more happiness, do that! I wish you nothing but happiness and delight, but you are the one who has to figure out what choices are going to bring that to you. 

I feel like Signal Data is less of a bottleneck than it has been in a long time.  It is available in every Weekly Shipment, the Guild Events Store, the Wandering Scavenger, and I get it in the Featured Shipment daily since I usually buy the 300 crystal pack at least once a day.  The good signal data is also now available in the Era Shipments as well.

If you are really in a pinch, break out your wallet and pick up one of the excellent values in the store.  I agree that the Vel Sartha farm (and possibly the IG-90 farm) are a little frustrating but Signal Data is very accessible at this stage in the game.  In fact I think a good argument can be made that Signal Data has never been more accessible than it is now.

I agree. Farming a cantina toon stops 90% of signal data income.  Which means stagnant progress in the game (which makes it less fun to play and the result is less players ...which hurts the game for everyone). How hard is it to have a yellow energy or fleet signal data node?  Just one node on those and it opens the bottleneck. I agree with some of the comments about choosing how to use resources.  But as it is now, there isn't much choice, it's either on or off. (11.7M account here). 

except they are doing just that since the recent era updates--and they said as such--making it easier for new players to catch up to the competition, offering cheaper/less resource demands, all the lightspeed tokens that bypass the tons of money and time i spent to build, now offered to newbies for cheap/free instant upgrades.

Its a resource management game.

You want to progress quickly, you pay, otherwise you need to be patient.

And? The aim of the game is to manage your resources. In recent weeks we have been given other means to get signal data.

As always to speed progress up you can spend money, otherwise you wait.

After all why do CG make us farm anything?!? Surely to avoid "stagnant progress" they should give all characters to us for free at relic 10? Sounds ridiculous? Of course it is, and thats where you and OP are being ridiculous too. (14.7m account here).

Well put. I wouldn't mind but in recent months and weeks we've been given extra ways of getting the various kinds of signal data too, including 25 dark blue a week worth 500 crystals.