The Arlec ones I recommended also have dry contacts inside their switched relays, and onboard power supplies. Same size as standard wall switch and a drop-in replacement. No POE wiring needed. Don’t over-complicate things and have to pull added cable, especially if it is behind walls filled with insulation like is common in more modern houses in Australia, and the yellow-tongue gets stuck on the noggins. If the slimline aspect is an issue, just replace it with a blank cover and install the new one adjacent in the wall - the wires should stretch. Remember you are paying your sparky by the hour, and the time required to simply swap over a familiar looking switch with another that also looks similar and just move the existing wires to the new unit, compared to reading Chinglish instructions and pulling added power wires is going to quickly sway the financial aspect.
You will find as you research even further that most automation light and power switches have a relay with dry contacts, as it is the cheapest way of switching mains power reliably and in a small package.
You do realise whatever device you connect, behind the wall or not, dry contacts or not, you will still be connecting the mains power to switch it, and the electrical connection work will need to be done by an electrician?
Have you checked out the SwitchRoo also described here in these forums? They may also offer a light switch version of their Deta modfed devices you also find at Bunnings. Support your home grown industries.
Your own custom firmware? The older versions had a ESP, and more recent ones have a Tekin chip on board. Both flashable for Tuya independence, and integrate well into HomeAssistant.
Both devices you have referenced sourced from AliExpress may not have the obligatory RCM certification, confirming your thoughts that no matter how attractive they may be in price, no electrician that is legally required to issue a certificate is going to risk losing his career by installing it.
Grumble, pay the ‘Aussie’ tax, get something compliant, fitted by an experienced professional, and sleep comfortably at night. Ask your family if the fifty bucks you save buying cheap Chinese stuff is worth it?