Shadow's inhibitor rings had different settings and stuff. G. U. N. Could control it/the settings thing broke when the whole incident happened. What if it was set to the highest maximum so that Chaos Energy could be siphoned?
With the settings broken and the maximum being on, Shadow would have to regulate how long the rings are on for. Take them off every once in a while (maybe once a day or week idk) so that he doesn't get weak. If he forgets to do that then he will get sick (which yes he is the ultimate lifeform and yes he shouldn't get sick but this is a his body issue not an external sickness so yes it could work).
I'd say the 3 general symptoms would be lethargy (sleepy/unresponsiveness), dizziness, and irritability (well, more irritable than at normal). There are definitely more symptoms but you probably want to keep doomscrolling so just enter "low energy symptoms" into Google and hopefully Gemini (that's what the ai is called right) will give more symptoms, but those are the main 3.
On the flip side, if he forgets to put them back on and gets too much energy, then he can't use his abilities without overshooting how much power he has and how much power he needs to use (like with the teleporting, he tries to go one place but overshoots and ends up in some random place) and gets downright restless (having to constantly move around because if he stands still he feels like he's gonna explode), and maybe a side of anxiety too (too much energy can play into anxiety, if Shadow is overflowing with Chaos Energy, there is the chance he'll become anxious). Oh yeah, and also probably a racing heart beat.
And yes, Tails could fix it (truth be told, he probably will once he figures out how too), but Shadow probably wouldn't willingly tell anyone about the whole situation. They gang would probably find out by finding Shadow unresponsive because of too little, or having an panic/anxiety attack because he forgot to put the rings back on and other causes.
Though, while Tails is figuring out the rings, if it takes a while, the group could remind him to regulate his energy.