OSOPRO. Think its a Taiwanese company? There are also knock offs motowolf (and others) that are pretty damn close and work fine. Only osopro uses the genuine 3m pad, all the others its something less good, if your phone is heavy, scrape it off and fit real 3m pad.
On motorbike use I this guy https://gsports.vn/mua/bo-khoa-kep-da-nang-chong-rung-osopro-lku121/
Phone is heavy, like 250g big fat 2024 brick of a phone, bikes been crashed, crashed into, ridden offroad extensively, phone is attached with a genuine 3m pad (included) to a normal case, never budged, even in 45c heat + strong sunlight and then crashed into various terrain. RECOMMEND.
But for MTB maybe tad too heavy. They do also have just the bracket and you can stick that on some normal bars, 31.8, won’t go to the 35 standard though as you don’t see that big in motorbikes, only dirt bikes, who puts a phone o on a dirt bike?