There are usually many solutions to these issues, some better than others.

In your case I notice that you are feeding the COMPARATOR output to the sidechain input of the GATE2. This may not work too well, at the comparator output is in effect DC, whereas the sidechain expects real audio..

Probably better to either:

1) Dump the comparator and send real audio to the sidechain input – you can then use the GATE2's threshold level to determine when it cuts in.

2) Or, if you really want on/off type control, use an AMPMOD instead of the GATE2. You would also need an ABS to constrain the COMPARATOR output to the range 0 to 1 (otherwise it will be -1 to +1).