There are three major aspects to consider when getting a mouse and especially when it comes to gaming, so here they are:
1. You must have a good grip on the mouse, meaning that there will be comfort at all times for your hand and in long sessions of playing games your hands will not get unnecessarily tired because they have to over-compensate for the lack of comfort while holding the mouse.
2. Precision, most games require a decent level of high response time in terms of aim and accuracy (example of this would be cs:go), therefore there is nothing other than a mouse that can give you the best of precision to aim specifically where you want it, you don’t want a mouse cursor that skips pixels and things like that. Though there may be things like gaming specific mousepads that can significantly help your accuracy.
3. Extra keys. Most of the time your left hand will be too busy with different keys to press along with movement and therefore relieving some pressure and stress out of your left hand to your right one where it’s usually just aiming at things will be a key advantage point to excel at playing competitive games.
The last point could also be tied with the first one because without comfort and especially extra-key pressing comfort you might end up playing under your potential due to discomfort while holding the mouse and pressing extra-keys that aren’t natural for your hand to press.
With that being said folks I reckon that any competent mouse will significantly improve the quality of your gaming time by so much that you won’t even consider using a regular mouse ever again, trust me I’ve been there and there’s no way my hands will ever touch a normal 2 click mouse that people use in offices at desk-jobs everywhere, it’s just horrible, the same way I won’t ever touch a non-mechanical keyboard.