Seiko 5 is probably the cheapest, worthwhile mechanical watch. You can always get cheap Chinese and Russian watches as well but they will be of lesser quality and reliability than the Seiko. So to answer your question directly - probably not. But I would recommend checking out Orient watches. They have a decent set of mechanical watches of all different styles, not much more expensive than the classic Seiko 5, but definitely a step up in quality. https://www.orientwatchusa.com/
Thickness is always going to be an issue with automatic watches. You can get thinner watches if they are manual wind since they don't have a rotor. Usually, the thinner they get, the more expensive they get though, so keep that in mind. You can get super thin manual wind watches but they will cost hundreds to thousands of dollars usually.
Thickness is always going to be an issue with automatic watches. You can get thinner watches if they are manual wind since they don't have a rotor. Usually, the thinner they get, the more expensive they get though, so keep that in mind. You can get super thin manual wind watches but they will cost hundreds to thousands of dollars usually.