You had me at the first half, not gonna lie

I can relate, but I feel any “solution” at this moment will bring enough problems that will outweigh the gains

Bluetooth Audio Transmitter will probably be your only choice here, but quality and latency will suffer.

Now... Does your headphones really need EQ this much to sound good in small handheld devices with somewhat low audio quality?

You don't need to upgrade for the sound, the BTR3 is powerful enough to drive any IEM. Update if you need a feature that yours doesn't have.

Had a BTR5, now I have a Qudelix 5k. Sound is the same (as it should be ffs), but the experience is much better, the app is constantly upgraded, with new features, lots of options, eq working with USB/BT is great. Really couldn't be happier

Perfection

And the party piece, it’s a BT Receiver. I didn’t need the extra power but wireless IEMs were too enticing to pass

Small and light, can drive any entry level headphone easily (and supports balanced 2.5 if you need more juice), amazing app with great parametric eq and autoeq support, chrome extension, supports PS4/5, can be used as a USB DAC

This is by far the best audio purchase anyone can make for the $110 (that is not an IEM).

Adding to what everyone else said, if you have and IEM and you use a tip that make you don't, you'll be losing a lot of bass (not to mention it will probably fall off more often than not.

"If it doesn't fit it will sound like shit"

Couldn't agree more. The app/chrome extension are amazing, continuous updates, PS5 compatibility and EQ over USB-C.

The additional power of the BTR7 will be "wasted" on the Timeless