I was told by the dealership that i need to replace my timing chain because i was rough on a small 2.0L engine....
This can after having infotainment unit issues for about a year and after all warning lights lit up on the dash recently.

Wondering if anyone else had the same diagnosis?

Seems weird since the timing chain was supposed to last a lifetime

 

^

1) How many miles on the 2021 RDX?
2) Did you have consistent regular maintenance performed?
3) Were you rough on the small 2.0L engine?

 

Only 100K on it. Maintained regularly. I drive fast but i never took the damn thing to the track...

 

Regardless of the alleged 'lifetime' timing chain duration & the admission of being rough on the 2.0L engine, it appears you obtained reasonable utility from a four cylinder trying to pull around the weight of a 3,783 to 4,068 pound vehicle, (depending on trim level).
Pay the piper & carry on or upgrade to more displacement to suit your preferred driving style?

 

Its a first one with timing chain issues, frequent oil changes help with timing chain wear.

 

What exactly did they diagnose and pinpoint for needing the chain replaced?

Generally guides and tensioner are the main points of failure, frequent Oil changes will help chain last the lifetime of the vehicle for sure.