"Loch" in Scots isn't cognate with German "Loch" meaning hole, it's from Scottish Gaelic "loch" meaning lake, and cognate with Latin "lacus", English "lake", and German "Lache". Scottish Gaelic is a close relative of Irish and sounds quite similar to it.
Edit: "reek" in Scots means "smoke" and is probably cognate with German "rauchen".
In modern usage, by speakers of Scottish English, it means "smelly". I'm not 100% sure, but I'm confident that "reek" in this context was borrowed from Scots and the meaning has just drifted over time.
Scottish Gaelic (Gàidhlig) and Irish Gaelic (Gaeilge, often just called "Irish") are both direct descendants of Middle Irish, which ultimately comes from a Celtic root. Gaidhlig gradually replaced Pictish, now extinct, about a thousand years ago.
I'm prone to false etymologies, so take this with a pinch of salt. Rauch and riechen, Geruch are probably related, too, only very far back and with lots of different influences in the mean time. I thought that rex, the dog name, could be related to riechen more than roy, king, because that's what they do. I thought so because Egyptian 'fnd' ("fenedj" - nose) does remind a little of 'find'. I'm quite fond of the idea. I reckon, with Egyptian 'rh' ("rekh" - to know), I become somewhat convinced of the idea. It could be from 'r' - mouth, 'hr' - head, top, chief.
Last time someone mentioned a possible connection from Egypt to Europe, it was quickly denounced. I'm not sure why.
There's more: 'rkh' - to burn; 'rh-nswt' - "acquaintance of the king" (nswt or nsw - king, god king; 'sw' - day, also 'hr' - day, if there's a connection from day to sun, sky, this could be analog to 'deus', 'divine', if I say so myself, otherwise 'swt' - sedge [a reed plant?] is considered as symbol of upper Egypt, giving king of the sedge; reeds, especially papyrus is related to writing and knowledge, so ... Ger. 'Gesetz' [law] is probably just from 'setzen' [set]; 'nswt' is not to be confused with German "Naseweiß" [cheeky, smart aleck]; 'rh' as ray is rather attractive, ie. rays of knowledge, rays of the sun figuratively as friends of the king, if connected to 'rkh' [to burn]); 'rht' - royal subjects, humanity [subjects of the king?]; 'rhs' - slaughter [from 'rkh' - to burn?]; 'rhn' - to depend on; 'rk' - time, age, era;
There's a discredited theory by Vennemann that linguistic evidence indicates Phonicians traveled from Spain to the north sea. There are actually finds of DNA that could corroborate something like this https://www.bbc.com/news/science-environment-35179269 - incidentally 'bbr' means babylon, one could think that's related to bereber. 'fnhw' - means and is the root of the word phoenician, but I'm not going to make jokes about anyone's nose, because the theory is that 'fnh' means carpenter. 'fn' means something like misery, by the way, Egypt had problems with Lybian Berbers. They say Jesus was a carpenter. This is getting out of hand, I don't know when to stop.
Common Scottish English usage I encounter daily: "that bin reeks", "my dog rolled in fox poo and she reeks", "I was reeking of sweat", "that place reeked".
For what it's worth - I'm from Perth, Australia (presumably named after Perth, Scotland), and we use the word the same way here. "Oh my god, that absolutely reeks" would be a common usage.
I'm in Montana and we have a local Loch. Except it's pronounced "Lock" (but still spelled "Loch"). But is isn't actually a Loch, just a reach of the river (that runs through it).
Edit: "reek" in Scots means "smoke" and is probably cognate with German "rauchen".