Sennheiser makes much better can than the TR126. Why don’t you move up the line?
I think the easiest recommendation would be to move up the Sennheiser line as there aren’t a ton of options in the RF headphone space. The RS175 is probably the best choice in terms of sound/features/price and a huge step up over what you have now, . If you don’t want to pay full price you can save a lot by buying factory-refurbished models from reputable sellers — I’ve done this with both my headphones and been very happy with both the quality and price in both cases. I think this would be an excellent option (refurbished by Sennheiser), and they offer a 30-day trial period so very low risk. Best of luck.