Admittedly it’s a short spell of googling but, isn’t it just a 166/167mm axle you need, which is to say (one of) a standard 142mm size?
(142 being the same actual hub size as 135 that sounds feasible and certainly the first few sizes I could find for the maxle agreed)
In either case you can’t just get a “142mm” and space it by (definitely) 7mm, there’s every chance the axle you buy may be shorter than you need or it could be longer by rather more than 7mm. 135/142/148/super duper boost aren’t axle sizes so beyond indicating you’re in the right ballpark they don’t tell you what you need to know. 142 for example would cover 4 standard lengths I think then the various thread options on top.
Some spacers is probably the way to go – I’ve previously put 2mm of spacer on the nds and put a few more turns of thread on an able to make it fit. I wouldn’t want to just thread it or just space it mind, if only because the lack of symmetry would upset me