Recommend hardware solution for multi rs485 channel?

I have three RS485 devices (each operating at 115200 baud) and one BNO08x IMU, which supports UART at 3,000,000 baud, as well as I2C and SPI.Currently, I am using three USB-to-RS485 adapters and one USB-to-UART adapter to connect these devices. This setup is bulky and inconvenient.I am looking for a more integrated solution, such as a single controller or I/O board, that can communicate with all these devices independently and reduce cabling and USB usage.Any recommendations?

Depends partly on how much data each device needs to transmit/receive, and how often. Theoretically, rs485 can multi-drop a large number of devices. I have used rs485 almost strictly via modbus protocol, but I see you do not mention modbus.

Using modbus rtu (rs485) with the mb2hal component, I was able to operate 1 VFD per converter/adapter. I was reading/writing approximately 16 parameters per VFD several times per second. I could not reliably run 2 VFDs on one converter. It seemed I was pushing the limits on bandwidth. But I had it running a lot slower - I think it was 9600, I needed that for better interference tolerance.

I used the ebyte NA111 ethernet bridge. They seem ok. Maybe a bit sensitive to interference. (I was using them in a large cabinet with one 30hp, one 10hp, two 5hp, and one 3hp 480VAC VFD, so there was plenty interference available and they've been running relatively reliably since about 4 month ago when they started using it.)

I also tried using the ebyte NE2-D11 but was very disappointed with it. It was so sensitive to interference it did not work with the Allen Bradley VFD I tried to interface. Well, it worked, but froze every time, the instant the VFD was started. I want to try it sometime on a sensor, or maybe even multiple sensors, I expect it might be fine for that.

I also have on another LinuxCNC installation a cheap USB to rs232 converter reading a position sensor about 50x per second nearly continuously since about 2016.