Determination of the frequency channel within the public group

Hello gentlemen, developers!
I am reading in the adjoining thread about the QR-link for a public channel within a region. Therefore, I have the following question:
For the Russian region, we have 2 channels in the vicinity of the 868.9 MHz frequency. Suppose we organized a public channel at frequency 1. Suppose the client’s lora module on part 1 detected an interference and automatically switched to frequency 2.

Questions:

  1. Will a client with interference on frequency 1 be able to connect to everyone else or to a radio relay?
  2. Do I need to build the firmware myself with 1 hard-coded channel for public use. Does everyone need to do this?
  3. This only applies to 2 channels. What if there are more regional channels?

The question arose due to the fact that yesterday I could not start the TTGO module on the 1st channel 433. For some reason, the module tuned itself to channel 5 (out of 10 or 20), where there was no interference and I cannot tune it in any way to other channels.

The devices do not change channels to avoid interference. The channel number is normally automatically selected by a hash of the channel name.