For men of short and slim stature, it is remarkably difficult to find clothing off-the-rack that fits well. If you're off a standard deviation or two from the typical RTW sizes, then you have essentially two strategies.
First, you can try your chances by finding a designer brand that cuts their suits, jackets, shirts trousers to a slimmer fitting overall. This is a rather hit and miss proposition as I have found over the years. But here are some ready-to-wear brands that currently offer or have offered slimmer clothing:
The second strategy is to go custom, namely, made to measure (MTM) or bespoke. My recommendation is to start with MTM and work upwards to full bespoke. One caveat is that custom made clothing requires more attention to detail and knowledge by the customer and is actually "riskier" from a handwork/production standpoint because there are more human hands involved (e.g. potentially more mistakes). However, the benefits are much better fit and better value in the long run. Unless you have special needs requiring bespoke (e.g. very sloped shoulders), I think it's an easier and more manageable learning curve to migrate from MTM to bespoke (as well as easier on the pocketbook).