The particular sounds that are "uncomfortable" aren’t just "bright" and your amp may not even be the biggest factor. You will make a lot more improvement eliminating small problems in a number of areas rather than trying to cure it all with one amp. At 64 I am well down the same road and know what I’m talking about.
A lot of the problem is ringing. Everything rings, the trick is to dissipate vibrations as quickly and uniformly as possible. Springs are great at this. Nobsound springs are cheap yet extremely effective. Townshend Pods are even better and in most cases would be recommended #1 for someone in your price range. With your particular concern however I think you really should try Nobsound first.
This is because Nobsound are more sensitive to tuning the sound by changing the number of springs or total load per spring. The difference is easy to hear and it allows a much wider range of adjustment than anything you will find with any amp. We are talking the difference between the most annoying solid state and the most syrupy smooth tube amps you can find.
Simply by changing the number of springs per footer, or the number of footers per component, you will be able to fine tune each one. The beauty of this is it is a two-fer: you get both better details and dynamics AND smoother more pleasant sound.
Not bad for $30/set.