I’d best post the obligatory Buffalo mountain shirt recommendation.
I’ve got a Buffalo MTB shirt from twenty-odd years ago that I still wear, but is a bit short and restricted for wearing much underneath.
So three weeks ago I bought a Special 6 smock top from a camping/outdoor shop in town, who gave me a discount so I got it for £148.
I’ve worn it to work every day since, and I love it! I work outdoors all day, and it’s very exposed to wind and rain, normally I’d be wearing a work issued tee shirt, sweat shirt, fleece and highviz waterproof jacket, and I’d be putting the tee in the wash as soon as I got home ‘cos it would be wet from sweating; I’m just wearing a Helly Lifa under the Special 6 with a buff or similar around my neck, and I’m so much more comfortable now.