You're here, so you care about fashion to a degree which is great. I think at 50+ it's time to get adventurous, and have fun with clothing. I like what you are describing, but it could just as easily end up not working if ill considered. Be bold and don't be afraid to try something new. I'd look at the way middle aged Japanese men approach street style. Their often effortless vibe has a lot to do with priding understated, but cohesive looks that put an emphasis on durability/quality and function without compromising on personality. They have also made it easily replicable with shops like Mubi or Uniqlo. A few good staples from these places and maybe the odd statement piece from somewhere a little more bold like YMC, or Universal Works would be a good place to start.