Klipsch Forte ii too bright, or is it my room ?

Individuals may have different capacity for what they perceive as brightness. For sure OP running wrong amp in wrong room, tube amp and some room treatments a good start if keeping Klipsch.
I have 1989 Klipschorns, had to redo the whole thing, but then I'm extremely sensitive to timbre anomalies.

I'd agree room would be first thing. Second could be wrap horn rather than change amp. I can only tell you the horn on my Klipschorn went from ringing like a bell to sounding like a damp rag. I tried everything from tiny to large amounts of various damping materials, no sense of natural timbre for me. Still, the damping could work for him if not as sensitive to timbre and tonal anomalies as myself. I still prefer tube amp vs ss amp on Klipsch Heritage, although I did have a little Musical Fidelity M2SI integrated ss in for a time that really wasn't too bad.

He needs to change only one variable at a time, changing room first may allow him to live with rest of system. If he intends on keeping Klipsch (which do have some admirable qualities even in stock form), damping the horns could be a next possible solution, assuming he still has issues with  brightness after only room treatments. Still has issues, go to tube amp, I, and many others who own Klipsch prefer tubes as we have the similar tonality/timbre issues with most ss amps.
He could explore the first two options with practically no cash outlay. If resources of no concern, I'd suggest the room fixes with professional treatments together with tube amp as initial moves.
Purchasing new speakers first upsets the entire balance of what he presently has, like starting all over again from scratch. Keep the Klipsch and proceed in incremental steps.

@audioman58 Way too much info for this thread, OP looking for simple fixes. I happen to agree with you, my Klipschorn, extreme mods.
I saw OP later post. He has idea of fixing room first, this is exactly how he should proceed. He then mentioned amp or new speaker next, Either could be best move for him.

Actually, without the mods, while I might not have been in hate group, call me lukewarm. Even in stock form I could hear the good and potential for better, even great. I'm sure being long time modder allowed me to hear potential. While my mods are not possible for many, there are some more simple mods that are effective in taming brightness. Yes, horn speakers are susceptible to tonal/timbre anomalies, but so are a lot of speakers.

I'd never advocate giving up on Klipsch Heritage, providing one is willing to work a bit. I also realize its not everyone's cup of tea, no harm, no foul.

+1 on room first. You'll never receive full value of any system in your room. Don't color the components, fix the room, then you can hear true sound signature of your system.