500L/mth is quite a bit! You're looking at small-scale commercial gear for that amount.
To give you an idea of what you're looking at, check this out:
https://www.grainandgrape.com.au/products/category/search/7BRAUM 200 LITRE--200-litre-braumeister
That's top-end gear for a small physical footprint, but it's quality German engineering & you're paying for it. You'd only need to brew twice a month, but it would need 3-phase power.
You'd also need large fermenters & all the packaging gear (ie. kegs) to go along with it (trust me, you'll soon get jack of bottling that amount on a monthly basis!). Depending on what you want, it can be cheap, or get pretty exy.
If you want to try something a bit smaller & cheaper, this sort of thing would be your best bet:
https://www.kegland.com.au/brewzilla-65l-gen-3.html You'd be able to knock-out about 50L at a time & requires a 15A circuit to handle the elements. They also have a 35L version that can be run from a standard 10A circuit, but you'd be brewing much more frequently.
Both of those units can be programmed to go through the steps required, so your actual physical "hands-on" presence during the brew-day is reduced over traditional (multi-vessel) systems.
There's ways of making much stronger wort with both of those units (ie. double-mashing), which can then be diluted for fermentation at regular strength, so you brew less frequently. It would make for a longer day, but overall, you'd be saving time.
'Hope that helps. Shoot me a PM if you've got any questions.