Okay, I'm gonna get try to point out as much as I can since I'll be out for most of the day.
First one will be a few questions. How fast is Metal's info analysis and how effective is it to things he does not know? Kuuga's suit was made before the start of human civilization, and possibly even predates that. I was told Metal can easily analyze Sonic, but isn't Metal a creation of Robotnik, shouldn't he already have info of Sonic before hand. Not only that, a living suit of armor which enhances the user to inhuman levels, grows in more power and properties, and is tens to hundreds of thousands of years old would be too complex for Metal to analyze quickly unless you guys actually give reasoning to what Metal has analyze.
Second, does Metal start off with his bubble shield and does he turn it off every so often? Simple really, just is it in character to have it on at all times.
Third is Metal's explosions. It's shown that Kuuga is not affected by his own explosions, if he is affected at all. When it comes from explosions, the damage that Kuuga takes is mitigated, he's been harmed by physical attacks from city busters before but when it comes to a city level explosion, he sat in the epicenter and got out with no trouble. While Metal's physical attacks will harm Kuuga, the damage he takes from explosions will be greatly mitigated. Not only that, Kuuga has healed from attack that would last over the course of years but regenerated over night. So any damage Metal has done will be undone fairly quickly.
Lastly, Kuuga's own explosions. The novelization of Kamen Rider Kuuga says
this. Whenever Kuuga places a marker, it injects sealing energy into the target, causing an explosion. Note that it's not "applies" or "places" energy, it injects energy. Metal being robotic wouldn't help against this since inside would be vital parts such as computer chips, data terminals, wires and stuff that makes machines run.
