Your struggles seem insurmountable which shouldn't be. You asked for reliability, brightness, visibility and overall ease of use and superior quality.
If you are not keen (which sounds like you are) on having spitwads, mud or whatever,you can use an adapter so you can use bulbs made for European Cars.
The 3156 or 3157 socket can be adapted to the European bulb sockets. Available on eBay--most distributors are here in CA.
Since most of this feature comes in luxury cars, perhaps one can trust its longevity/reliability IMO.
If your vehicle is over two years old, chances are the electronics, whether the software or hardware have been superseded in one way or another...in other words trailing along the footprints of T-Rex.
Turnover for this stuff is eighteen months at least. . . . . well as an automotive aficionado I'm sure you know.
The CAN (controller area network) Bus is a standard for most modern cars, as one poster had said.
The CAN Bus LEDs are special bulbs with a built-in IC chip to simulate the characteristics of a filament bulb. This IC will eliminate the 50W 6 ohm resistor. A bit pricey but not too much to break the bank.
Since these are made to work with the car's ECU, the built-in IC will eliminate the need for an on-board computer---it fools your flasher mechanism to make it look like a filament bulb is intact and functional.
There are electronic flashers on the market but I doubt they are DOT approved.
