Note those are 2 wires from the same direction commonly used in motors
Where the power comes in and connects to the stator in a tight space
The way professionals create a “tight 90” in this case is by crimping lugs on then bolting the 2 wires at the angle needed then insulating.
the downside to this method is the cost 2 lugs, cambric /2520 And liner-less /130 are normally used with regular tape it gets a bit expensive but you can make a 90 this way.
I don’t think I have ever seen a inline 90 degree splice.
Because of code requirements for box fill / sizing they would rarely be used so the cost would be high and we would just bolt the lugs together and insulate with tape as mentioned vs paying a high price so the DIY market would be the only use and in reality this is tiny in the electrical world.