Some options to consider:
Meditate on what it means for ISO to be high.
Use the 35/1.8. You can't get the shot you want with it, but you might still not get the shot you want with the zoom lens.
Use slower shutter speeds. 1/125 may be faster than necessary. Since you state you are using the zoom lens for focal lengths wider than 35mm, 1/60 should be fine. Even slower if your lens has image stabilization. I use 1/40 throughout the zoom range of my kit lens (18-55). I use 1/100 for non-stabilized lenses (up to 135mm).
Use a flash (with diffuser or bounce), or find some other way to add light.
Post process to remove noise or convert to black and white.
Put the camera down and just enjoy the moment.
Get new lenses. Here are some that might work:
24mm or 28mm prime (any make)
24-70/2.8 or similar (any make)
Sigma 24-35/2 Art
Sigma 18-35/1.8 Art
Slower constant aperture (F3.5, F4) lenses may be helpful if you find yourself drawn to the long end.
Faster variable aperture lenses are available (F2.8-4), but image quality at F2.8 isn't great on the ones I've tried.
Try a focal reducer?Too bad... They don't work on DSLRs.Get a new camera that produces less (objectionable) noise at high ISOs.
The end result is that I have... lots of shots with ISOs higher than I'd like. The image quality is not terrible at those ISOs, but...
It's not clear to me whether you want lower ISO values for the sake of having lower ISO values or whether you actually find the noise that results from high ISOs objectionable.
For instance, I don't like chroma noise, such as may be seen in flolilo's sample image. But I don't mind more monochromatic noise, which my camera tends to produce. So even though I'd like lower ISO values, I let my camera run up to ISO 12800 because I know I'd miss the shot otherwise. However, if I do need cleaner images, I find ways to add more light.
Here's an image taken with a Sigma 18-200/3.5-6.3 at 69mm F4, 1/125 sec, ISO 8000. You can view it at 100% to see what noise from my camera looks like. (No colored specks.)
Here's an image taken with a Canon FD 35-105/3.5 at 105mm F3.5, 1/75 sec, ISO 12800. There is a near absence of green light, which means the sensor was working at only about 45% capacity. (Non-standard color matrix with green sensels covering about 55% of the sensor.) I converted to black and white because I couldn't make color work without the green channel.
