Prior to corona, there were usually about 5 PL games at 3pm Saturday (which are not televised in the UK), 1 at 12:30pm and 5:30pm Saturday, 1 at 2pm and 4:30pm Sunday, and 1 on Monday night, with the occasional game on Friday nights as well. With corona they're spreading the games out more but there's no indication this will continue once crowds return to stadiums.
In any case, regardless of who ends up with the rights they should make sure to schedule A-League games so that there isn't overlap with the Premier League during the European season, which means finishing up by 9:30pm/11:30pm on Saturdays and 11pm/1am on Sundays. No point trying to compete with other football matches.
I can see Perth games being on Friday nights (9:45pm AEST or so) during the European season, and switching to Saturday nights at the same time in the off-season.