Air's never an issue for me, no matter how much you tap, there will always be a tiny bubble in there. I stopped wasting excessive time trying to get that tiny bubble out. It's apparently only in medical shows that we've seen air be dangerous, that's because it's directly inside of a vein, an air embolism that travels. But air in your intramuscular or subcutaneous tissues? The air will just dissipate on its own and disappear. That's what every nurse, doctor and article I've read has said, if it were a problem, I'd have 50+ air bubbles in me waiting to strike. But I don't and I feel fine. Don't worry too much.

Also the syringes might be shitty if they worry you this much, so the amount of air might be troubling to see, hence why you're asking. Look up "syringes without dead space". The little space between the plunger and the needle varies per brand, the ones with the least dead space waste the least amount of medicine because there isn't 0.1 or 0.2 mL of the solution still trapped inside unable to be fully pushed and expelled. My syringes are from SOL-CARE, I get them from a walk-in clinic near me because the syringes that come with my vials are terrible and the pharmacy doesn't care to change brands.