I’m a HA noob and this is my first little project. And I’m french so sorry for my english level…
To change to any channel I needed to simulate multiple button press with a 1sec delay between each.
Here how I achieved this (I think there is lots of improvements to make, do not hesitate to comment 
1 - I made a script for each number of my tv’s remote (0 to 9):
tv_0:
alias: TV - 0
sequence:
- service: broadlink.send_packet_xxx_xxx_xxx_xxx
data:
packet:
- "JgBQAAABJZISOBITExITEhMSEhMSExITEzcSExI4EjgSOBM3EzcTNxMSEzcTEhMSEzcTEhMSEzcTNxMSEzcUNRUREzcTNxQRFAAFKgABJUkSAA0FAAAAAAAAAAA="
[......]
tv_9:
alias: TV - 9
sequence:
- service: broadlink.send_packet_xxx_xxx_xxx_xxx
2 - I made an IFTTT recipe : Google assistant : “Channel #” that calls a script.change_channel service with the number as a “channel” variable:
change_channel:
alias: "Changement de chaine"
sequence:
- service: python_script.set_channel
data_template:
channel: "{{channel}}"
3 - The Python script component set_channel.py is just here to fire an event (this is the worst part of my workflow…) :
channel = data.get('channel')
hass.bus.fire('change_channel', {'channel': channel})
4 - The event change_channel is catched by an appdaemon script set_channel.py (yes, same name… 
):
import appdaemon.appapi as appapi
#
# Change Channel on TV
# To call it, fire a change_channel event with a "channel" json param
#
# Args :
# prefix: remote's button scripts format (exemple : "prefix: lg_channel_" will call script.lg_channel_0 to script.lg_channel_9)
#
class SetChannel(appapi.AppDaemon):
def initialize(self):
self.log("SetChannel loaded")
self.listen_event(self.do_change, 'change_channel')
def do_change(self, event_name, data, kwargs):
self.log("Changing channel for {}".format(data["channel"]))
delay = 0
for c in str(data["channel"]):
if delay == 0:
self.do_channel({"channel": c}) # Got a bug with run_in if delay = 0...
else:
self.run_in(self.do_channel, delay, channel = c)
delay += 1
def do_channel(self, kwargs):
target = "script.{}{}".format(self.args["prefix"], kwargs["channel"])
self.log("Pressing remote button {} - call script {}".format(kwargs["channel"], target))
self.turn_on(target)
My module config:
set channel:
module: set_channel
class: SetChannel
prefix: tv_
And yeaaaah !
It’s working for any channel 
Not much, but proud of it 
cheers
