Rentvesting vs PPOR & ETFs?

Hey all,

Me and my partner are looking to move in together sometime in the next 12-24 months.

This would be a DINKs household, we both make around 80k give or take before tax and excluding super.

She holds a PPOR apartment in inner city Melbourne whilst I still live at home (moved back after covid).

Currently, I believe the mortgage is owing about 580k approx. down from about 800-900k initial loan. Variable at 5.39% or around that. P&I.

Valuations of the property I believe are around 900k-over 1 mill as it is a 3 bedroom in an area with mostly 2 bedroom apartments. She currently rents two bedrooms out whilst she lives in the remainder to service the mortgage.

I have accrued around 400k in equity, bonds & cash over the years. She holds most of her wealth in the PPOR and offset.

I guess the question is two scenarios not so much what should we do? But what is the trade off pros and cons?

1. I move in with her and we service the mortgage together:

Obviously this is the easier option, already furnished, good location, etc. However, wouldn't be able to claim deductions, no rental income, I would have to pay 50% of the monthly repayments (around $3,500 iirc).

Obviously that means I'm subsiding her equity growth so may discuss with her with nothing to show. And ownership in her mortgage is off the table for the time being due to her parents having ownership etc so that's a whole different kettle of fish.

2. We move into a place to rent elsewhere and rent out the apartment as a investment property:

Obviously can claim investment property deductions, can potentially rent the third room out for more income, but partner is thinking of renting entire thing out which is less messy and more control but less overall income.

I also read about the 6 year rule? If you don't nominate another PPOR you can preserve CGT exemption? Idk if this is the right choice or viable.

I also don't particulary want to realise GCT on my equity and put into the PPOR or another investment property. I have leveraged stocks as I realise the major strength of property is the ability to over-leverage proportionate to equity. Luckily some newer leveraged ETFs are coming to market in recent years that aren't are susceptible to volatility decay due to lower gearing. (1.5x threshold vs 2.5x or higher).

I do realise that as she has a PPOR, and I have equities, we are very well diversified currently.

However, a healthy mind is an open one so I am open to counter-points and any recommendations or advice.

Thanks!