You didnt buy your TV from Roku - its a TCL TV you bought from a retailer (online or offline).
The issue with NF isnt "in part" on "NetFlix' end" its entirely on NF's end (again, NF codes and develops and publishes the app).
That remote with a NF button was manufactured by TCL, not Roku.
If the "whole TV interface is laggy and glitchy", that speaks to a major hardware/OS issue - again, that's TCL's to handle.
But your OP didnt mention general lagging and glitching, only NF crashing (which isnt very descriptive - you need to explain exactly what you mean by "NetFlix crashing").
Do other apps "crash"?
FYI, the correct procedure to re-install an app on Roku:
1) Remove the app (Highlight the app, press the Options (*) button on the remote, then Remove)
2) RESTART the Roku (Settings/System/Power/System restart/Restart) <-- MUST DO THIS HERE!!!
3) Re-install the app
(Otherwise, settings/cached data associated with the app are left behind and it wont be a clean re-install).