2010 Polaris Ranger 800 engine issues

Hello all, I’m new here and have issues lol. I have a 2010 Polaris Ranger 800 crew. Recently rebuilt the motor, original motor had a piston end up sideways inside the cylinder. Got another motor and made 1 out of 2. Replaced the exhaust manifold, spark plugs, all gaskets, impeller, tps, air intake sensor, crank sensor and I think that’s it. Before the old motor blew it had codes 27 and 41 present which is why I changed 2 of the sensors (but they weren’t oem replacements just Amazon ones with good ratings) before I go on and on about everything I’ll get to my point. The exhaust manifold is now glowing red hot after running for just a couple minutes. The glow seems to die down when giving it throttle though. This led me to thinking maybe the exhaust is clogged. Cut the muffler open and cleaned it out and braised it back together, pipes are clean as far as I can tell and still glows. Taking the muffler off it still glows red but takes longer to glow and doesn’t seem to glow as bright. Codes 27 and 41 are still showing, and being the glow seemed to die down some with throttle I was thinking the motor is running lean.
So I’m stuck at do I spend the $100 plus on a new air intake sensor and hope it works, new injectors (fuel pressure was within range at the rail) or an entirely new exhaust?

Any ideas or has anyone experienced anything like this? Thank you all in advance for any guidance. The pictures below are idle (first picture) and under load (second picture)